Organic electroluminescence element, and material for organic electroluminescence element

ABSTRACT

The organic electroluminescence device includes an anode, a cathode, and at least an emitting layer between the anode and the cathode. The emitting layer includes a first host material, a second host material, and a phosphorescent dopant material. The first host material is a compound represented by a formula (1) below and the second host material is a compound represented by a formula (2) below.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. Non-Provisional applicationSer. No. 14/353,774, which was filed on Apr. 24, 2014. U.S.Non-Provisional application Ser. No. 14/353,774 is a National Stage ofPCT/JP2012/077690, which was filed on Oct. 26, 2012. This application isbased upon and claims the benefit of priority to Japanese ApplicationNo. 2011-235491, which was filed on Oct. 26, 2011.

TECHNICAL FIELD

The present invention relates to an organic electroluminescence deviceand a material for the organic electroluminescence device.

BACKGROUND ART

There has been known an organic electroluminescence device (hereinafter,referred to as an “organic EL device”) that includes an emitting unit(in which an emitting layer is included) between an anode and a cathodeand emits light using exciton energy generated by a recombination ofholes and electrons that have been injected into the emitting layer.

A phosphorescent organic EL device using a phosphorescent dopantmaterial as a luminescent material has been known as the organic ELdevice. The phosphorescent organic EL device can achieve a high luminousefficiency by using a singlet state and a triplet state of excitedstates of the phosphorescent dopant material. The reason is presumed asfollows. When holes and electrons are recombined in the emitting layer,it is presumed that singlet excitons and triplet excitons are producedat a rate of 1:3 due to difference in spin multiplicity. Accordingly,luminous efficiency of the device using a phosphorescent material canreach three to four times as much as that of the device using only afluorescent material.

Patent Literature 1 describes that a compound in which anitrogen-containing heterocyclic group is bonded to an arylcarbazoylgroup or a carbazoyl alkylene group is suitable to a phosphorescent hostmaterial usable in combination with a phosphorescent dopant material. Anorganic EL device driven at a low voltage and having a high color purityis obtainable by using the phosphorescent dopant material and thiscompound in the emitting layer.

CITATION LIST Patent Literature

Patent Literature 1: International Publication No. WO2003/080760

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

However, since the phosphorescent host material described in PatentLiterature 1 has a large HOMO, hole injection into the emitting layer isdifficult. Accordingly, emission occurs at an interface of a holetransporting layer, resulting in a short lifetime.

An object of the invention is to provide a long-life organicelectroluminescence device exhibiting a high luminous efficiency and amaterial for the organic electroluminescence device.

Means for Solving the Problems

After conducting concentrated studies in order to achieve the object,the inventors have found that a long-life organic electroluminescencedevice exhibiting a high luminous efficiency is obtainable in a combineduse of a specific first host material and a specific second hostmaterial in an emitting layer. The invention has been achieved based onthese findings.

An organic electroluminescence device according to an aspect of theinvention includes an anode, a cathode, and at least an emitting layerbetween the anode and the cathode, the emitting layer including a firsthost material, a second host material, and a phosphorescent dopantmaterial, in which the first host material is a compound represented bya formula (1) below and the second host material is a compoundrepresented by a formula (2) below.

In the formula (1), Z¹ represents a cyclic structure fused at a of theformula (1) and represented by the formula (1-1) or (1-2); Z² representsa cyclic structure fused at b of the formula (1) and represented by theformula (1-1) or (1-2); at least one of Z¹ and Z² is represented by theformula (1-1); M¹ represents a substituted or unsubstitutednitrogen-containing heteroaromatic ring having 5 to 30 ring atoms; L¹represents a single bond or a linking group, the linking group being oneor a combination of a substituted or unsubstituted aryl group having 6to 30 ring carbon atoms, a substituted or unsubstituted heterocyclicgroup having 5 to 30 ring atoms, and a cycloalkyl group having 5 to 30ring carbon atoms; and m is 1 or 2.

In the formulae (1-1) and (1-2): c, d, e, f are fused at a or b in theformula (1); R¹¹ and R³¹ each independently represent a hydrogen atom, ahalogen atom, a cyano group, a substituted or unsubstituted aryl grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedheterocyclic group having 5 to 30 ring atoms, a substituted orunsubstituted alkyl group having 1 to 30 carbon atoms, a substituted orunsubstituted alkenyl group having 2 to 30 carbon atoms, a substitutedor unsubstituted alkynyl group having 2 to 30 carbon atoms, asubstituted or unsubstituted alkylsilyl group having 3 to 30 carbonatoms, a substituted or unsubstituted arylsilyl group having 6 to 30ring carbon atoms, a substituted or unsubstituted alkoxy group having 1to 30 carbon atoms, a substituted or unsubstituted aralkyl group having6 to 30 ring carbon atoms, or a substituted or unsubstituted aryloxygroup having 6 to 30 ring carbon atoms; a plurality of R¹¹ are mutuallythe same or different; a plurality of R³¹ are mutually the same ordifferent; adjacent groups of R¹¹ may be bonded with each other to forma ring; X³ is a sulfur atom, an oxygen atom or N—R³² or C(R³²)₂; and R³²represents the same as R¹¹ and R³¹.

Herein, N—R₂ represents a bond of a single R₂ and a nitrogen atom (N)and C(R₂)₂ represents a bond of two R₂ and a carbon atom (C).

In the formula (2), R² independently represents a hydrogen atom, ahalogen atom, a cyano group, a substituted or unsubstituted aryl grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedheterocyclic group having 5 to 30 ring atoms, a substituted orunsubstituted alkyl group having 1 to 30 carbon atoms, a substituted orunsubstituted alkenyl group having 2 to 30 carbon atoms, a substitutedor unsubstituted alkynyl group having 2 to 30 carbon atoms, asubstituted or unsubstituted alkylsilyl group having 3 to 30 carbonatoms, a substituted or unsubstituted arylsilyl group having 6 to 30ring carbon atoms, a substituted or unsubstituted alkoxy group having 1to 30 carbon atoms, a substituted or unsubstituted aralkyl group having6 to 30 ring carbon atoms, or a substituted or unsubstituted aryloxygroup having 6 to 30 ring carbon atoms.

In the formula (2), p and q are independently an integer of 0 to 4; aplurality of R² are mutually the same or different.

Adjacent groups of R² may be bonded with each other to form a ring.

In the formula (2), L² represents a single bond or a linking group, thelinking group being one or a combination of a substituted orunsubstituted aryl group having 6 to 30 ring carbon atoms, one or acombination of a substituted or unsubstituted heterocyclic group having5 to 30 ring atoms, and a cycloalkyl group having 5 to 30 ring carbonatoms.

In the formula (2), FA represents a substituted or unsubstituted fusedaromatic cyclic group having 6 to 30 ring carbon atoms, or a substitutedor unsubstituted fused aromatic heterocyclic group having 5 to 30 ringatoms.

In the organic electroluminescence device according to the above aspectof the invention, the first host material is preferably represented by aformula (3) below.

In the formula (3): Z¹ represents a cyclic structure fused at a of theformula (3) and represented by the formula (1-1) or a formula (1-2); Z²represents a cyclic structure fused at b of the formula (3) andrepresented by the formula (1-1) or (1-2); at least one of Z¹ and Z² isrepresented by the formula (1-1); L¹ represents the same as L¹ of theformula (1); X¹ is a nitrogen atom or C—R¹⁰ and at least one of aplurality of X¹ is a nitrogen atom; R¹ and represent the same as R¹¹ ofthe formula (1-1); and m and n each are an integer of 1 to 2.

In the formulae (1-1) and (1-2), c, d, e, f are fused at a or b of theformula (3) in the formulae (1-1) and (1-2).

In the organic electroluminescence device according to the above aspectof the invention, the first host material is more preferably representedby a formula (4) below.

In the formula (4), L¹ represents the same as L¹ of the formula (1); X¹is a nitrogen atom or C—R¹⁰ and at least one of a plurality of X¹ is anitrogen atom; R¹, R¹⁰ and R¹¹ represent the same as R¹¹ of the formula(1-1); and m and n each are an integer of 1 to 2.

In the organic electroluminescence device according to the above aspectof the invention, the first host material is more preferably representedby a formula (5) below.

In the formula (5): L¹ and R¹ respectively represent the same as L¹ andR¹ of the formula (1); R¹¹ represents the same as R¹¹ of the formula(1-1); L³ and L⁴ represent the same as L¹ of the formula (1); X¹ is anitrogen atom or C—R¹⁰ and at least one of a plurality of X¹ is anitrogen atom; R¹⁰ represents the same as R¹¹ of the formula (1-1); n isan integer of 1 to 2; M³ represents a substituted or unsubstituted arylgroup having 6 to 30 ring carbon atoms, or a substituted orunsubstituted heterocyclic group having 5 to 30 ring atoms; h and k arean integer of 0 to 4; and i and j are an integer of 0 to 3.

In the organic electroluminescence device according to the above aspectof the invention, the second host material is preferably represented bythe formula (2) in which FA is a substituted or unsubstituted fusedaromatic cyclic group having 2 to 5 fused rings, or a substituted orunsubstituted fused aromatic heterocyclic group having 2 to 5 fusedrings.

In the organic EL device according to the above aspect of the invention,the second host material is preferably represented by the formula (2) inwhich FA is represented by a formula (2-4) below.

In the formula (2-A): Y represents O, S, NR²¹ or C(R²¹)₂; and R² and R²¹represent the same as R² of the formula (2).

However, one of R² is a single bond to be bonded with L² in the formula(2). When Y is C(R²¹)₂, a plurality of R²¹ are mutually the same ordifferent.

r and s are an integer of 0 to 4.

In the organic EL device according to the above aspect of the invention,the second host material is preferably represented by the formula (2) inwhich FA is represented by any one of formulae (2-1) to (2-4).

In the formulae (2-1) to (2-4), R² and R²¹ represent the same as R² ofthe formula (2).

However, one of R² is a single bond to be bonded with L² in the formula(2).

r and s are an integer of 0 to 4.

In the organic EL device according to the above aspect of the invention,the second host material is preferably represented by the formula (2) inwhich FA is represented by the formula (2-1) or (2-2).

In the organic EL device according to the above aspect of the invention,an emission peak wavelength of the phosphorescent dopant material ispreferably in a range of 490 nm to 700 nm.

A material for an organic electroluminescence device according toanother aspect of the invention includes a compound represented by theformula (1) and a compound represented by the formula (2).

In the material for the organic electroluminescence device according tothe above aspect of the invention, the compound represented by theformula (1) is preferably represented by the formula (3).

Further, in the material for the organic electroluminescence deviceaccording to the above aspect of the invention, the compound representedby the formula (1) is preferably represented by the formula (4).

In the material for the organic electroluminescence device according tothe above aspect of the invention, the compound represented by theformula (1) is more preferably represented by the formula (5).

In the material for the organic electroluminescence device according tothe above aspect of the invention, the second host material ispreferably represented by the formula (2) in which FA is a substitutedor unsubstituted fused aromatic cyclic group having 2 to 5 fused rings,or a substituted or unsubstituted fused aromatic heterocyclic grouphaving 2 to 5 fused rings.

In the material for the organic EL device according to the above aspectof the invention, the second host material is preferably represented bythe formula (2) in which FA is represented by a formula (2-A) below.

In the material for the organic electroluminescence device according tothe above aspect of the invention, the second host material ispreferably represented by the formula (2) in which FA is represented byany one of the formulae (2-1) to (2-4).

In the material for the organic EL device according to the above aspectof the invention, the second host material is more preferablyrepresented by the formula (2) in which FA is represented by the formula(2-1) or (2-2).

According to the invention, a long-life organic electroluminescencedevice exhibiting a high luminous efficiency and a material for theorganic electroluminescence device can be provided.

BRIEF DESCRIPTION OF DRAWING

FIG. 1 schematically shows an exemplary arrangement of an organic ELdevice according to a first exemplary embodiment of the invention.

FIG. 2 schematically shows an exemplary arrangement of an organic ELdevice according to a second exemplary embodiment.

FIG. 3 schematically shows an exemplary arrangement of an organic ELdevice according to a third exemplary embodiment.

FIG. 4 schematically shows an exemplary arrangement of an organic ELdevice according to a fourth exemplary embodiment.

FIG. 5 schematically shows an exemplary arrangement of an organic ELdevice according to a fifth exemplary embodiment.

DESCRIPTION OF EMBODIMENTS First Exemplary Embodiment

Arrangement of Organic EL Device

Arrangement(s) of an organic electroluminescence device (hereinafterreferred to as an organic EL device) of the invention will be describedbelow.

The following are representative arrangement examples of the organic ELdevice:

(1) anode/emitting layer/cathode;

(2) anode/hole injecting layer/emitting layer/cathode;

(3) anode/emitting layer/electron injecting⋅transporting layer/cathode;

(4) anode/hole injecting layer/emitting layer/electroninjecting⋅transporting layer/cathode; and

(5) anode/hole injecting⋅transporting layer/emitting layer/electroninjecting⋅transporting layer/cathode.

While the arrangement (5) is preferably used among the above, thearrangement of the invention is not limited to the above arrangements.

Note that the aforementioned “emitting layer” is an organic layerincluding a host material and a dopant material typically through adoping system. Typically, the host material promotes a recombination ofelectrons and holes and transmits exciton energy generated by therecombination to the dopant material. The dopant material is preferablya compound having a high quantum yield. The dopant material exhibits ahigh luminescent performance after receiving exciton energy from thehost material.

The “hole injecting/transporting layer (or hole injecting⋅transportinglayer)” means “at least one of a hole injecting layer and a holetransporting layer” while the “electron injecting/transporting layer (orelectron injecting⋅transporting layer)” means “at least one of anelectron injecting layer and an electron transporting layer.” Herein,when the hole injecting layer and the hole transporting layer areprovided, the hole injecting layer is preferably closer to the anode.When the electron injecting layer and the electron transporting layerare provided, the electron injecting layer is preferably closer to thecathode.

Next, an organic EL device 1 according to a first exemplary embodimentwill be shown in FIG. 1.

The organic EL device 1 includes a transparent substrate 2, an anode 3,a cathode 4, a hole transporting layer 6, an emitting layer 5 and anelectron transporting layer 7.

The hole transporting layer 6, the emitting layer 5, the electrontransporting layer 7 and the cathode 4 are sequentially laminated on theanode 3.

Emitting Layer

The emitting layer 5 contains a first host material, a second hostmaterial and a phosphorescent dopant material.

It is preferable that the first host material is set in a range of 10mass % to 90 mass %, the second host material is set in a range of 10mass % to 90 mass %, and the phosphorescent dopant material is set in arange of 0.1 mass % to 30 mass % such that a total mass percentage ofthe materials contained in the emitting layer 5 is equal to 100 mass %.More preferably, the first host material is set in a range of 40 mass %to 60 mass %.

First Host Material

As the first host material used in the organic EL device of thisexemplary embodiment, a compound represented by the above formula (1) isusable.

The “nitrogen-containing heteroaromatic ring” represented by M¹ in theformula (1) includes an azine ring.

Examples of the nitrogen-containing heteroaromatic ring represented byM¹ in the formula (1) are pyridine, pyrimidine, pyrazine, triazine,aziridine, azaindolizine, indolizine, imidazole, indole, isoindole,indazole, purine, pteridine, β-carboline, naphthyridine, quinoxaline,terpyridine, bipyridine, acridine, phenanthroline, phenazine andimidazopyridine.

Particularly, pyridine, pyrimidine and triazine are preferable. Thefirst host material is preferably represented by the formula (3).

Here, a compound to which the cyclic structures represented by theformulae (1-1) and (1-2) are fused at a and b in the formula (3) isexemplified by compounds represented by the following formulae.

The first host material is more preferably represented by the formula(4), particularly preferably represented by the formula (5).

Groups represented by R¹, R¹⁰ to R¹¹ and R³¹ to R³² in the formulae (1),(3) to (5), (1-1) and (1-2) will be described.

Examples of the aryl group having 6 to 30 ring carbon atoms are a phenylgroup, a 1-naphthyl group, a 2-naphthyl group, a 1-anthryl group, a2-anthryl group, a 9-anthryl group, a benzanthryl group, a 1-phenanthrylgroup, a 2-phenanthryl group, a 3-phenanthryl group, a 4-phenanthrylgroup, a 9-phenanthryl group, a naphthacenyl group, a pyrenyl group, a1-chrysenyl group, a 2-chrysenyl group, a 3-chrysenyl group, a4-chrysenyl group, a 5-chrysenyl group, a 6-chrysenyl group, abenzo[c]phenanthryl group, a benzo[g]chrysenyl group, a 1-triphenylenylgroup, a 2-triphenylenyl group, a 3-triphenylenyl group, a4-triphenylenyl group, a 1-fluorenyl group, a 2-fluorenyl group, a3-fluorenyl group, a 4-fluorenyl group, a 9-fluorenyl group, abenzofluorenyl group, a dibenzofluorenyl group, a 2-biphenylyl group, a3-biphenylyl group, a 4-biphenylyl group, an o-terphenyl group, anm-terphenyl-4-yl group, an m-terphenyl-3-yl group, an m-terphenyl-2-ylgroup, a p-terphenyl-4-yl group, a p-terphenyl-3-yl group, ap-terphenyl-2-yl group, an m-quarterphenyl group, a 3-fluoranthenylgroup, a 4-fluoranthenyl group, an 8-fluoranthenyl group, a9-fluoranthenyl group, a benzofluoranthenyl group, an o-tolyl group, anm-tolyl group, a p-tolyl group, a 2,3-xylyl group, a 3,4-xylyl group, a2,5-xylyl group, a mesityl group, an o-cumenyl group, an m-cumenylgroup, a p-cumenyl group, a p-t-butylphenyl group, ap-(2-phenylpropyl)phenyl group, a 4′-methylbiphenylyl group, and a4″-t-butyl-p-terphenyl-4-yl group.

The aryl group preferably has 6 to 20 ring carbon atoms, more preferably6 to 12 ring carbon atoms. Among the aryl group, a phenyl group, abiphenyl group, a naphthyl group, phenanthryl group, a terphenyl groupand a fluorenyl group are particularly preferable. With respect to a1-fluorenyl group, a 2-fluorenyl group, a 3-fluorenyl group and a4-fluorenyl group, a carbon atom at a position 9 is preferablysubstituted by a substituted or unsubstituted alkyl group having 1 to 30carbon atoms.

Examples of the heterocyclic group having 5 to 30 ring atoms are apyroryl group, a pyrazinyl group, a pyridinyl group, an indolyl group,an isoindolyl group, an imidazolyl group, a furyl group, a benzofuranylgroup, an isobenzofuranyl group, a dibenzofuranyl group, adibenzothiophenyl group, a quinolyl group, an isoquinolyl group, aquinoxalinyl group, a carbazolyl group, a phenantridinyl group, anacridinyl group, a phenanthrolinyl group, a phenazinyl group, aphenothiazinyl group, a phenoxazinyl group, an oxazolyl group, anoxadiazolyl group, a furazanyl group, a thienyl group, a benzothiopheylgroup, and a group formed from a pyridine ring, a pyrazine ring, apyrimidine ring, a pyridazine ring, a triazine ring, an indol ring, aquinoline ring, an acridine ring, a pirrolidine ring, a dioxane ring, apiperidine ring, a morpholine ring, a piperadine ring, a carbazole ring,a furan ring, a thiophene ring, an oxazole ring, an oxadiazole ring, abenzoxazole ring, a thiazole ring, a thiadiazole ring, a benzothiazolering, a triazole ring, an imidazole ring, a benzimidazole ring, a pyranering and a dibenzofuran ring.

More specifically, the examples of the heterocyclic group having 5 to 30ring atoms include a 1-pyroryl group, a 2-pyroryl group, a 3-pyrorylgroup, a pyrazinyl group, a 2-pyridinyl group, a 2-pyrimidinyl, a4-pyrimidinyl, a 5-pyrimidinyl group, a 6-pyrimidinyl group, a1,2,3-triazine-4-yl group, a 1,2,4-triazine-3-yl group, a1,3,5-triazine-2-yl group, a 1-imidazolyl group, a 2-imidazolyl group, a1-pyrazolyl group, a 1-indolidinyl group, a 2-indolidinyl group, a3-indolidinyl group, a 5-indolidinyl group, a 6-indolidinyl group, a7-indolidinyl group, an 8-indolidinyl group, a 2-imidazopyridinyl group,a 3-imidazopyridinyl group, a 5-imidazopyridinyl group, a6-imidazopyridinyl group, a 7-imidazopyridinyl group, an8-imidazopyridinyl group, a 3-pyridinyl group, a 4-pyridinyl group, a1-indolyl group, a 2-indolyl group, a 3-indolyl group, a 4-indolylgroup, a 5-indolyl group, a 6-indolyl group, a 7-indolyl group, a1-isoindolyl group, a 2-isoindolyl group, a 3-isoindolyl group, a4-isoindolyl group, a 5-isoindolyl group, a 6-isoindolyl group, a7-isoindolyl group, a 2-furyl group, a 3-furyl group, a 2-benzofuranylgroup, a 3-benzofuranyl group, a 4-benzofuranyl group, a 5-benzofuranylgroup, a 6-benzofuranyl group, a 7-benzofuranyl group, a1-isobenzofuranyl group, a 3-isobenzofuranyl group, a 4-isobenzofuranylgroup, a 5-isobenzofuranyl group, a 6-isobenzofuranyl group, a7-isobenzofuranyl group, a 2-quinolyl group, a 3-quinolyl group, a4-quinolyl group, a 5-quinolyl group, a 6-quinolyl group, a 7-quinolylgroup, an 8-quinolyl group, a 1-isoquinolyl group, a 3-isoquinolylgroup, a 4-isoquinolyl group, a 5-isoquinolyl group, a 6-isoquinolylgroup, a 7-isoquinolyl group, an 8-isoquinolyl group, a 2-quinoxalinylgroup, a 5-quinoxalinyl group, a 6-quinoxalinyl group, a 1-carbazolylgroup, a 2-carbazolyl group, a 3-carbazolyl group, a 4-carbazolyl group,a 9-carbazolyl group, an azacarbazolyl-1-yl group, an azacarbazolyl-2-ylgroup, an azacarbazolyl-3-yl group, an azacarbazolyl-4-yl group, anazacarbazolyl-5-yl group, an azacarbazolyl-6-yl group, anazacarbazolyl-7-yl group, azacarbazolyl-8-yl group, anazacarbazolyl-9-yl group, a 1-phenanthrydinyl group, a 2-phenanthrydinylgroup, a 3-phenanthrydinyl group, a 4-phenanthrydinyl group, a6-phenanthrydinyl group, a 7-phenanthrydinyl group, an 8-phenanthrydinylgroup, a 9-phenanthrydinyl group, a 10-phenanthrydinyl group, a1-acridinyl group, a 2-acridinyl group, a 3-acridinyl group, a4-acridinyl group, a 9-acridinyl group, a 1,7-phenanthroline-2-yl group,a 1,7-phenanthroline-3-yl group, a 1,7-phenanthroline-4-yl group, a1,7-phenanthroline-5-yl group, a 1,7-phenanthroline-6-yl group, a1,7-phenanthroline-8-yl group, a 1,7-phenanthroline-9-yl group, a1,7-phenanthroline-10-yl group, a 1,8-phenanthroline-2-yl group, a1,8-phenanthroline-3-yl group, a 1,8-phenanthroline-4-yl group, a1,8-phenanthroline-5-yl group, a 1,8-phenanthroline-6-yl group, a1,8-phenanthroline-7-yl group, a 1,8-phenanthroline-9-yl group, a1,8-phenanthroline-10-yl group, a 1,9-phenanthroline-2-yl group, a1,9-phenanthroline-3-yl group, a 1,9-phenanthroline-4-yl group, a1,9-phenanthroline-5-yl group, a 1,9-phenanthroline-6-yl group, a1,9-phenanthroline-7-yl group, a 1,9-phenanthroline-8-yl group, a1,9-phenanthroline-10-yl group, a 1,10-phenanthroline-2-yl group, a1,10-phenanthroline-3-yl group, a 1,10-phenanthroline-4-yl group, a1,10-phenanthroline-5-yl group, a 2,9-phenanthroline-1-yl group, a2,9-phenanthroline-3-yl group, a 2,9-phenanthroline-4-yl group, a2,9-phenanthroline-5-yl group, a 2,9-phenanthroline-6-yl group, a2,9-phenanthroline-7-yl group, a 2,9-phenanthroline-8-yl group, a2,9-phenanthroline-10-yl group, a 2,8-phenanthroline-1-yl group, a2,8-phenanthroline-3-yl group, a 2,8-phenanthroline-4-yl group, a2,8-phenanthroline-5-yl group, a 2,8-phenanthroline-6-yl group, a2,8-phenanthroline-7-yl group, a 2,8-phenanthroline-9-yl group, a2,8-phenanthroline-10-yl group, a 2,7-phenanthroline-1-yl group, a2,7-phenanthroline-3-yl group, a 2,7-phenanthroline-4-yl group, a2,7-phenanthroline-5-yl group, a 2,7-phenanthroline-6-yl group, a2,7-phenanthroline-8-yl group, a 2,7-phenanthroline-9-yl group, a2,7-phenanthroline-10-yl group, a 1-phenazinyl group, 2-phenazinylgroup, a 1-phenothiazinyl group, a 2-phenothiazinyl group, a3-phenothiazinyl group, a 4-phenothiazinyl group, a 10-phenothiazinylgroup, a 1-phenoxazinyl group, a 2-phenoxazinyl group, a 3-phenoxazinylgroup, a 4-phenoxazinyl group, a 10-phenoxazinyl group, a 2-oxazolylgroup, a 4-oxazolyl group, a 5-oxazolyl group, a 2-oxadiazolyl group, a5-oxadiazolyl group, a 3-furazanyl group, a 2-thienyl group, a 3-thienylgroup, a 2-methylpyrrole-1-yl group, a 2-methylpyrrole-3-yl group, a2-methylpyrrole-4-yl group, a 2-methylpyrrole-5-yl group, a3-methylpyrrole-1-yl group, a 3-methylpyrrole-2-yl group, a3-methylpyrrole-4-yl group, a 3-methylpyrrole-5-yl group, a2-t-butylpyrrole-4-yl group, a 3-(2-phenylpropyl)pyrrole-1-yl group, a2-methyl-1-indolyl group, a 4-methyl-1-indolyl group, a2-methyl-3-indolyl group, a 4-methyl-3-indolyl group, a2-t-butyl-1-indolyl group, a 4-t-butyl-1-indolyl group, a2-t-butyl-3-indolyl group, a 4-t-butyl-3-indolyl group, a1-dibenzofuranyl group, a 2-dibenzofuranyl group, a 3-dibenzofuranylgroup, a 4-dibenzofuranyl group, a 1-dibenzothiophenyl group, a2-dibenzothiophenyl group, a 3-dibenzothiophenyl group, a4-dibenzothiophenyl group, a 1-silafluorenyl group, a 2-silafluorenylgroup, a 3-silafluorenyl group, a 4-silafluorenyl group, a1-germafluorenyl group, a 2-germafluorenyl group, a 3-germafluorenylgroup and a 4-germafluorenyl group.

The heterocyclic group preferably has 5 to 20 ring atoms, morepreferably 5 to 14 ring atoms. Among the above heterocyclic group, a1-dibenzofuranyl group, a 2-dibenzofuranyl group, a 3-dibenzofuranylgroup, a 4-dibenzofuranyl group, a 1-dibenzothiophenyl group, a2-dibenzothiophenyl group, a 3-dibenzothiophenyl group, a4-dibenzothiophenyl group, a 1-carbazolyl group, a 2-carbazolyl group, a3-carbazolyl group, a 4-carbazolyl group, and a 9-carbazolyl group arepreferable. With respect to a 1-carbazolyl group, a 2-carbazolyl group,a 3-carbazolyl group, and a 4-carbazolyl group, a nitrogen atom at aposition 9 is preferably substituted by a substituted or unsubstitutedaryl group having 6 to 30 ring carbon atoms or a substituted orunsubstituted heterocyclic group having 5 to 30 ring atoms.

The alkyl group having 1 to 30 carbon atoms may be linear, branched orcyclic. Examples of the linear or branched alkyl group are a methylgroup, ethyl group, propyl group, isopropyl group, n-butyl group,s-butyl group, isobutyl group, t-butyl group, n-pentyl group, n-hexylgroup, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group,n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group,n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecylgroup, neo-pentyl group, 1-methylpentyl group, 2-methylpentyl group,1-pentylhexyl group, 1-butylpentyl group, 1-heptyloctyl group,3-methylpentyl group, hydroxymethyl group, 1-hydroxyethyl group,2-hydroxyethyl group, 2-hydroxyisobutyl group, 1,2-dihydoroxyethylgroup, 1,3-dihydroxyisopropyl group, 2,3-dihydroxy-t-butyl group,1,2,3-trihydroxypropyl group, chloromethyl group, 1-chloroethyl group,2-chloroethyl group, 2-chloroisobutyl group, 1,2-dichloroethyl group,1,3-dichloroisopropyl group, 2,3-dichloro-t-butyl group,1,2,3-trichloropropyl group, bromomethyl group, 1-bromoethyl group,2-bromoethyl group, 2-bromoisobutyl group, 1,2-dibromoethyl group,1,3-dibromoisopropyl group, 2,3-dibromo-t-butyl group,1,2,3-tribromopropyl group, iodomethyl group, 1-iodoethyl group,2-iodoethyl group, 2-iodoisobutyl group, 1,2-diiodoethyl group,1,3-diiodoisopropyl group, 2,3-diiodo-t-butyl group, 1,2,3-triiodopropylgroup, aminomethyl group, 1-aminoethyl group, 2-aminoethyl group,2-aminoisobutyl group, 1,2-diaminoethyl group, 1,3-diaminoisopropylgroup, 2,3-diamino-t-butyl group, 1,2,3-triaminopropyl group,cyanomethyl group, 1-cyanoethyl group, 2-cyanoethyl group,2-cyanoisobutyl group, 1,2-dicyanoethyl group, 1,3-dicyanoisopropylgroup, 2,3-dicyano-t-butyl group, 1,2,3-tricyanopropyl group,nitromethyl group, 1-nitroethyl group, 2-nitroethyl group,1,2-dinitroethyl group, 2,3-dinitro-t-butyl group and1,2,3-trinitropropyl group.

Examples of the cyclic alkyl group (cycloalkyl group) are a cyclopropylgroup, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a4-methylcyclohexyl group, a 3,5-tetramethylcyclohexyl group, acycloheptyl group, a cyclooctyl group, a 1-adamantyl group, a2-adamantyl group, a 1-norbornyl group, and a 2-norbornyl group.

The linear or branched alkyl group preferably has 1 to 10 carbon atoms,more preferably 1 to 6 ring atoms. Among the linear or branched alkylgroup, a methyl group, an ethyl group, a propyl group, an isopropylgroup, an n-butyl group, an s-butyl group, an isobutyl group, a t-butylgroup, an n-pentyl group and an n-hexyl group are preferable.

The cycloalkyl group preferably has 3 to 10 ring carbon atoms, morepreferably 5 to 8 ring carbon atoms. Among the cycloalkyl group, acyclopentyl group and a cyclohexyl group are preferable.

A halogenated alkyl group provided by substituting an alkyl group with ahalogen atom is exemplified by one provided by substituting an alkylgroup having 1 to 30 carbon atoms with one or more halogen groups.Examples of the halogenated alkyl group are a fluoromethyl group, adifluoromethyl group, a trifluoromethyl group, a fluoroethyl group and atrifluoromethylmethyl group.

The alkenyl group having 2 to 30 carbon atoms may be linear, branched orcyclic. Examples of alkenyl group having 2 to 30 carbon atoms are avinyl group, a propenyl group, a butenyl group, an oleyl group, aneicosapentaenyl group, a docosahexaenyl group, a styryl group, a2,2-diphenylvinyl group, a 1,2,2-triphenylvinyl group and a2-phenyl-2-propenyl group. Among the alkenyl group, the vinyl group ispreferable.

The alkynyl group having 2 to 30 carbon atoms may be linear, branched orcyclic. Examples of the alkynyl group having 2 to 30 carbon atoms are anethynyl group, a propynyl group and a 2-phenylethynyl group. Among thealkenyl group, the ethynyl group is preferable.

The alkylsilyl group having 3 to 30 carbon atoms is exemplified by analkylsilyl group having the alkyl group listed as the examples of thealkyl group having 1 to 30 carbon atoms. Specifically, examples of thealkylsilyl group are a trimethylsilyl group, a triethylsilyl group, atri-n-butylsilyl group, a tri-n-octylsilyl group, a triisobutylsilylgroup, a dimethylethylsilyl group, a dimethylisopropylsilyl group, adimethyl-n-propylsilyl group, a dimethyl-n-butylsilyl group, adimethyl-t-butylsilyl group, a diethylisopropylsilyl group, avinyldimethylsilyl group, a propyldimethylsilyl group andtriisopropylsilyl group. The three alkyl groups may be mutually the sameor different.

Examples of the arylsilyl group having 6 to 30 ring carbon atoms are adialkylarylsilyl group, an alkyldiarylsilyl group and a triarylsilylgroup.

The dialkylarylsilyl group is exemplified by a dialkylarylsilyl groupincluding two of the alkyl group listed as the examples of the alkylgroup having 1 to 30 carbon atoms and one of the aryl group listed asthe examples of the aryl group having 6 to 30 ring carbon atoms. Thedialkylarylsilyl group preferably has 8 to 30 carbon atoms. The twoalkyl groups may be mutually the same or different.

The alkyldiarylsilyl group is exemplified by an alkyldiarylsilyl groupincluding one of the alkyl group listed as the examples of the alkylgroup having 1 to 30 carbon atoms and two of the aryl group listed asthe examples of the aryl group having 6 to 30 ring carbon atoms. Thealkyldiarylsilyl group preferably has 13 to 30 carbon atoms. The twoaryl groups may be mutually the same or different.

The triarylsilyl group is exemplified by a triarylsilyl group includingthree of the aryl group listed as the examples of the aryl group having6 to 30 ring carbon atoms. The triarylsilyl group preferably has 18 to30 carbon atoms. The three aryl groups may be mutually the same ordifferent.

Examples of the arylsilyl group are a phenyldimethylsilyl group, adiphenylmethylsilyl group, a diphenyl-t-butylsilyl group and atriphenylsilyl group.

The alkoxy group having 1 to 30 carbon atoms is represented by —OY. Y isexemplified by the alkyl group having 1 to 30 carbon atoms. The alkoxygroup is preferably an alkoxy group having 1 to 6 carbon atoms, examplesof which are a methoxy group, an ethoxy group, a propoxy group, a butoxygroup, a pentyloxy group, and a hexyloxy group.

A halogenated alkoxy group provided by substituting an alkoxy group witha halogen atom is exemplified by one provided by substituting an alkoxygroup having 1 to 30 carbon atoms with one or more halogen groups.

The aralkyl group having 6 to 30 ring carbon atoms is represented by—Y—Z. Y is exemplified by an alkylene group formed from the alkyl grouphaving 1 to 30 carbon atoms. Z is exemplified by the aryl group having 6to 30 ring carbon atoms. The aralkyl group is preferably an aralkylgroup having 7 to 30 carbon atoms, in which an aryl portion has 6 to 30carbon atoms, preferably 6 to 20 carbon atoms, more preferably 6 to 12carbon atoms, and an alkyl portion has 1 to 30 carbon atoms, preferably1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, furtherpreferably 1 to 6 carbon atoms. Examples of the aralkyl group include: abenzyl group, a 2-phenylpropane-2-yl group, a 1-phenylethyl group, a2-phenylethyl group, a 1-phenylisopropyl group, a 2-phenylisopropylgroup, a phenyl-t-butyl group, an α-naphthylmethyl group, a1-α-naphthylethyl group, a 2-α-naphthylethyl group, a1-α-naphthylisopropyl group, a 2-α-naphthylisopropyl group, aβ-naphthylmethyl group, a 1-β-naphthylethyl group, a 2-β-naphthylethylgroup, a 1-β-naphthylisopropyl group, a 2-β-naphthylisopropyl group, a1-pyrorylmethyl group, a 2-(1-pyroryl)ethyl group, a p-methylbenzylgroup, an m-methylbenzyl group, an o-methylbenzyl group, ap-chlorobenzyl group, an m-chlorobenzyl group, an o-chlorobenzyl group,a p-bromobenzyl group, an m-bromobenzyl group, an o-bromobenzyl group, ap-iodobenzyl group, an m-iodobenzyl group, an o-iodobenzyl group, ap-hydroxybenzyl group, an m-hydroxybenzyl group, an o-hydroxybenzylgroup, a p-aminobenzyl group, an m-aminobenzyl group, an o-aminobenzylgroup, a p-nitrobenzyl group, an m-nitrobenzyl group, an o-nitrobenzylgroup, a p-cyanobenzyl group, an m-cyanobenzyl group, an o-cyanobenzylgroup, a 1-hydroxy-2-phenylisopropyl group and a1-chloro-2-phenylisopropyl group.

The aryloxy group having 6 to 30 ring carbon atoms is represented by—OZ. Z is exemplified by the aryl group having 6 to 30 ring carbon atomsor a monocyclic group and a fused cyclic group described below. Thearyloxy group is exemplified by a phenoxy group.

Examples of the halogen atom are a fluorine atom, a chlorine atom, abromine atom and a iodine atom, among which the fluorine atom ispreferable.

The aryl group having 6 to 30 ring carbon atoms and the heterocyclicgroup having 5 to 30 ring carbon atoms, which are represented by L¹, L³and L⁴ in the above formulae (1) and (3) to (5), are exemplified by adivalent group formed from the above groups.

Examples of the cycloalkyl group having 5 to 30 ring carbon atoms are acyclopentylene group, a cyclohexylene group, and a cyclohepthylenegroup.

The aryl group having 6 to 30 ring carbon atoms and the heterocyclicgroup having 5 to 30 ring carbon atoms, which are represented by M³ inthe above formula (5), are exemplified by the above groups.

In the invention, “carbon atoms forming a ring (ring carbon atoms)” meancarbon atoms forming a saturated ring, an unsaturated ring, or anaromatic ring. “Atoms forming a ring (ring atoms)” mean carbon atoms andhetero atoms forming a hetero ring including a saturated ring, anunsaturated ring, or an aromatic ring.

Examples of a substituent which may be used in a case of being“substituted or unsubstituted” are an hydroxyl group, a nitro group anda carboxy group in addition to an aryl group, a heterocyclic group, analkyl group (a linear or branched alkyl group, a cycloalkyl group and ahalogenated alkyl group), an alkenyl group, an alkynyl group, analkylsilyl group, an arylsilyl group, an alkoxy group, a halogenatedalkoxy group, an aralkyl group, an aryloxy group, a halogen atom, and acyano group as described above. Among the above substituents, an arylgroup, a heterocyclic group, an alkyl group, a halogen atom, analkylsilyl group, an arylsilyl group and a cyano group are preferable.More preferable substituents are one listed as the preferablesubstituents described for each substituent. The substituents may befurther substituted by the aforementioned substituents.

The same applies to the substituents of “substituted or unsubstituted”in compounds or a partial structure thereof described below.

In the invention, a hydrogen atoms encompasses isotopes having differentnumbers of neutrons, specifically, protium, deuterium and tritium.

Examples of the compounds represented by any one of the formulae (1) to(5) are as follows. Note that a bond without a formula (e.g., Ph, CN anda benzene ring) at an end represents a methyl group in the followingstructures.

Second Host Material

As the second host material used in the organic EL device of thisexemplary embodiment, a compound represented by the above formula (2) ispreferable.

In the formula (2), an aryl group, an heterocyclic group, an alkylgroup, an alkenyl group, an alkynyl group, an alkylsilyl group, anarylsilyl group, an alkoxy group, an aralkyl group and an aryloxy grouprepresented by R² are the same as those described in relation to R¹, R¹⁰to R¹¹ and R³¹ to R³² in the formula (1) and the like.

In the formula (2), an aryl group, a heterocyclic group and a cycloalkylgroup represented by L² are the same as those described in relation toL¹ in the formula (1).

In the formula (2), FA represents a substituted or unsubstituted fusedaromatic cyclic group having 6 to 30 ring carbon atoms, or a substitutedor unsubstituted fused aromatic heterocyclic group having 5 to 30 ringatoms.

FA is preferably a substituted or unsubstituted fused aromatic cyclicgroup having 10 to 30 ring carbon atoms, or a substituted orunsubstituted fused aromatic heterocyclic group having 9 to 30 ringatoms, more preferably a substituted or unsubstituted fused aromaticcyclic group having 2 to 5 fused rings, or a substituted orunsubstituted fused aromatic heterocyclic group having 2 to 5 fusedrings.

FA is further preferably represented by a formula (2-A) below.

In the formula (2-A): Y represents O, S, NR²¹ or C(R²¹)₂; and R² and R²¹represent the same as R² of the formula (2).

However, one of R² is a single bond to be bonded with L² in the formula(2). When Y is C(R²¹)₂, a plurality of R²¹ are mutually the same ordifferent.

r and s are an integer of 0 to 4.]

Among these groups, FA is more preferably represented by any one of thefollowing formulae (2-1) to (2-4), particularly preferably by theformula (2-1) or (2-2).

In the formulae (2-1) to (2-4), R² and R²¹ represent the same as R² ofthe formula (2).

However, one of R² is a single bond to be bonded with L² in the formula(2).

r and s are an integer of 0 to 4.]

Examples of the fused aromatic cyclic group for FA are a naphthyl group,phenanthryl group, fluoranthenyl group, triphenylenyl group,phenanthrenyl group, fluorenyl group, spirofluorenyl group, 9,9-diphenylfluorenyl group, 9,9′-spirobi[9H-fluorene]-2-yl group,9,9-dimethylfluorenyl group, benzofluorenyl group, benzo[c]phenanthrenylgroup, benzo[a]triphenylenyl group, naphtho[1,2-c]phenanthrenyl group,naphtho[1,2-a]triphenylenyl group, dibenzo[a,c]triphenylenyl group,benzo[b]fluoranthenyl group, chrysenyl group and pyrenyl group.

The fused aromatic cyclic group for FA more preferably has 6 to 20 ringcarbon atoms, and further preferably has 6 to 12 ring carbon atoms.Among the fused aromatic cyclic group, a naphthyl group, phenanthrylgroup, triphenylenyl group, fluorenyl group, 9,9-dimethylfluorenylgroup, spirobifluorenyl group and fluoranthenyl group are particularlypreferable. With respect to a fluorenyl group, a carbon atom at aposition 9 is preferably substituted by a substituted or unsubstitutedalkyl group having 1 to 30 carbon atoms.

Examples of the fused aromatic heterocyclic group for FA are groupsformed from an isoindole ring, benzofuran ring, isobenzofuran ring,dibenzothiophene ring, isoquinoline ring, quinoxaline ring,phenanthrizine ring, phenanthroline ring, indole ring, quinoline ring,acridine ring, carbazole ring, benzoxazole ring, benzothiazole ring,benzimidazole ring, dibenzofuran ring, benzo[c]dibenzofuran ring,phenazine ring, phenothiazine ring, phenoxazine ring, azacarbazole ring,imidazopyridine ring, azatriphenylene ring, azadibenzofuran ring andderivatives thereof, among which a dibenzofuran ring, carbazole ring,dibenzothiophene ring, quinoxaline ring and derivatives thereof arepreferable. With respect to a carbazolyl group, a nitrogen atom at aposition 9 is preferably substituted by a substituted or unsubstitutedaryl group having 6 to 30 ring carbon atoms or a substituted orunsubstituted heterocyclic group having 5 to 30 ring atoms. The arylgroup having 6 to 30 ring carbon atoms and the heterocyclic group having5 to 30 ring atoms are the same as those described above in relation tothe first host material.

In the formulae (2), (2-A) and (2-1) to (2-4), when L², R², R²¹ and FAhave one or more substituents, the substituent(s) is the same as thoseof the formula (1).

Examples of the compound represented by the formula (2) are as follows.Note that a bond without a formula (e.g., Ph, CN and a benzene ring) atan end represents a methyl group in the following structures.

Phosphorescent Dopant Material

The phosphorescent material preferably contains a metal complex, and themetal complex preferably has a metal atom selected from Ir (iridium), Pt(platinum), Os (osmium), Au (gold), Cu (copper), Re (rhenium) and Ru(ruthenium), and a ligand. Particularly, the ligand preferably has anortho-metal bond.

The phosphorescent material is preferably a compound containing a metalselected from Ir, Os and Pt because such a compound, which exhibits highphosphorescence quantum yield, can further enhance external quantumefficiency of the organic EL device. The phosphorescent material is morepreferably a metal complex such as an iridium complex, osmium complex orplatinum complex, among which an iridium complex and platinum complexare more preferable and ortho metalation of an iridium complex is themost preferable. The organic metal complex formed of the ligand selectedfrom the group consisting of phenyl quinoline, phenyl isoquinoline,phenyl pyridine, phenyl pyrimidine, phenyl pyrazine, phenyl imidazoleand benzoquinoline is preferable in terms of luminous efficiency and thelike.

Examples of such a preferable metal complex are shown below.

One of the phosphorescent dopant materials may be used alone, or two ormore thereof may be used in combination.

At least one phosphorescent material contained in the emitting layer 5preferably has an emission wavelength peak in a range of 490 nm to 700nm, more preferably in a range of 490 nm to 650 nm, further preferablyin a range of 490 nm to 600 nm. An emission color of the emitting layer5 in the exemplary embodiment is preferably yellow or green. Though anemission wavelength peak of yellow is typically in a range of 530 nm to620 nm, the emission wavelength is particularly preferably in a range of550 nm to 600 nm in the exemplary embodiment.

By doping the phosphorescent dopant material having such an emissionwavelength to the aforementioned specific first and second hostmaterials so as to form the emitting layer 5, the organic EL device canexhibit high efficiency.

Substrate

The organic EL device 1 is configured to include the anode 3, theemitting layer 5 and the cathode 4 laminated on the light-transmissivesubstrate. The substrate 2, which supports the anode 3 and the like, ispreferably a flat and smooth substrate that transmits 50% or more oflight in a visible region of 400 nm to 700 nm.

The light-transmissive plate is exemplarily a glass plate, a polymerplate or the like.

The glass plate is formed of soda-lime glass,barium/strontium-containing glass, lead glass, aluminosilicate glass,borosilicate glass, barium borosilicate glass, quartz, and the like.

The polymer plate is formed of polycarbonate, acryl, polyethyleneterephthalate, polyether sulfide, polysulfone and the like.

Anode and Cathode

The anode 3 of the organic EL device 1 is used for injecting holes intothe hole injecting layer, the hole transporting layer 6 or the emittinglayer 5. It is effective that the anode 3 has a work function of 4.5 eVor more.

Specific examples of a material for the anode are alloys of indium-tinoxide (ITO), tin oxide (NESA), indium zinc oxide, gold, silver, platinumand copper.

The anode 3 is producible by forming a thin film of these anodematerials through methods such as vapor deposition and sputtering, forinstance, on the substrate 2.

When light from the emitting layer 5 is to be emitted through the anode3, the anode 3 preferably transmits more than 10% of the light in thevisible region. Sheet resistance of the anode 3 is preferably severalhundreds Ω/sq. or lower. Although depending on the material of the anode3, a thickness of the anode 3 is typically in a range of 10 nm to 1 μm,preferably in a range of 10 nm to 200 nm.

The cathode is preferably formed of a material with smaller workfunction in order to inject electrons into the emitting layer.

Although the material for the cathode is subject to no specificlimitation, examples of the material are indium, aluminum, magnesium,alloy of magnesium and indium, alloy of magnesium and aluminum, alloy ofaluminum and lithium, alloy of aluminum, scandium and lithium, alloy ofmagnesium and silver and the like.

Like the anode 3, the cathode 4 is also producible by forming a thinfilm through a method such as vapor deposition or sputtering, forinstance, on the electron transporting layer 7. In addition, the lightfrom the emitting layer 5 may be emitted through the cathode 4. Whenlight from the emitting layer 5 is to be emitted through the cathode 4,the cathode 4 preferably transmits more than 10% of the light in thevisible region.

Sheet resistance of the cathode is preferably several hundreds Ω/sq. orlower.

Although depending on the material of the cathode, a thickness of thecathode is typically in a range of 10 nm to 1 μm, preferably in a rangeof 50 nm to 200 nm.

Other Layers

In order to improve current (luminous) efficiency, a hole injectinglayer, a hole transporting layer, an electron injecting layer and thelike may be provided. The organic El device 1 includes the holetransporting layer 6 and the electron transporting layer 7.

Hole Transporting Layer

The hole transporting layer 6 helps injection of holes to the emittinglayer and transports the holes to an emitting region. The holetransporting layer 6 exhibits a large hole mobility and a smallionization potential.

A hole transporting material for forming the hole transporting layer 6is preferably a material of transporting the holes to the emitting layer5 at a lower electric field intensity. For instance, the second hostmaterial represented by the formula (2) in the exemplary embodiment isusable. In addition, an aromatic amine derivative represented by thefollowing formula (A1) is preferably used as the material for the holetransporting layer 6.

In the formula (A1), Ar¹ to Ar⁴ each represent: an aromatic hydrocarbongroup having 6 to 50 ring carbon atoms, a fused aromatic hydrocarbongroup having 6 to 50 ring carbon atoms, an aromatic heterocyclic grouphaving 2 to 40 ring carbon atoms, a fused aromatic heterocyclic grouphaving 2 to 40 ring carbon atoms, a group provided by bonding thearomatic hydrocarbon group and the aromatic heterocyclic group, a groupprovided by bonding the aromatic hydrocarbon group and the fusedaromatic heterocyclic group, a group provided by bonding the fusedaromatic hydrocarbon group and the aromatic heterocyclic group, and agroup provided by bonding the fused aromatic hydrocarbon group and thefused aromatic heterocyclic group.

The aromatic hydrocarbon group, the fused aromatic hydrocarbon group,the aromatic heterocyclic group and the fused aromatic heterocyclicgroup described above may be substituted.

In the formula (A1), L is a linking group and represents a divalentaromatic hydrocarbon group having 6 to 50 ring carbon atoms, a divalentfused aromatic hydrocarbon group having 6 to 50 ring carbon atoms, adivalent aromatic heterocyclic group having 5 to 50 ring carbon atoms, adivalent fused aromatic heterocyclic group having 5 to 50 ring carbonatoms, or a divalent group including two or more of an aromatichydrocarbon group or an aromatic heterocyclic group with a single bond,an ether bond, a thioether bond, an alkylene group having 1 to 20 carbonatoms, an alkenylene group having 2 to 20 carbon atoms, or an aminogroup.

The divalent aromatic hydrocarbon group, the divalent fused aromatichydrocarbon group, the divalent aromatic heterocyclic group and thedivalent fused aromatic heterocyclic group described above may besubstituted.

Examples of the compound represented by the formula (A1) are shownbelow. However, the compound is not limited thereto.

Aromatic amine represented by the following formula (A2) is alsopreferably usable for forming the hole transporting layer.

In the formula (A2), Ar¹ to Ar³ each represent the same as thoserepresented by Ar¹ to Ar⁴ of the above formula (A1). Examples of thecompound of the formula (A2) are shown below. However, the compound ofthe formula (A2) is not limited thereto.

Although depending on a combination with the first host material, thesecond host material and the phosphorescent dopant material in theemitting layer 5, the hole transporting material preferably exhibits anionization potential Ip(HT) in a range of 5.3 eV to 5.7 eV.

Electron Transporting Layer

The electron transporting layer 7, which helps injection of electrons tothe emitting layer 5, has a high electron mobility.

In this exemplary embodiment, the electron transporting layer 7 isprovided between the emitting layer 5 and the cathode, and the electrontransporting layer 7 preferably contains a nitrogen-containing cyclicderivative as the main component. The electron injecting layer may serveas the electron transporting layer.

Note that “as the main component” means that the nitrogen-containingcyclic derivative is contained in the electron transporting layer 7 at acontent of 50 mass % or more.

A preferable example of an electron transporting material for formingthe electron transporting layer 7 is an aromatic heterocyclic compoundhaving at least one heteroatom in a molecule. Particularly, anitrogen-containing cyclic derivative is preferable. Thenitrogen-containing cyclic derivative is preferably an aromatic ringhaving a nitrogen-containing six-membered or five-membered ringskeleton, or a condensed aromatic cyclic compound having anitrogen-containing six-membered or five-membered ring skeleton.

A preferable example of the nitrogen-containing cyclic derivative is anitrogen-containing cyclic metal chelate complex represented by thefollowing formula (B1).

In the formula (B1), R² to R⁷ independently represent a hydrogen atom, ahalogen atom, an oxy group, an amino group, a hydrocarbon group having 1to 40 carbon atoms, an alkoxy group, an aryloxy group, an alkoxycarbonylgroup, or an aromatic heterocyclic group, which may be substituted.

Examples of the halogen atom are fluorine, chlorine, bromine and iodine.Examples of a substituted or unsubstituted amino group are an alkylaminogroup, an arylamino group and an aralkylamino group.

The alkoxycarbonyl group is represented by —COOY′. Examples of Y′ arethe same as the examples of the alkyl group. The alkylamino group andthe aralkylamino group are represented by —NQ¹Q². Examples for each ofQ¹ and Q² are independently the same as the examples described inrelation to the alkyl group and the aralkyl group, and preferableexamples for each of Q¹ and Q² are also the same as those described inrelation to the alkyl group and the aralkyl group. One of Q¹ and Q² maybe a hydrogen atom. Note that the aralkyl group is provided bysubstituting a hydrogen atom of the alkyl group with the aryl group.

The arylamino group is represented by —NAr¹Ar². Examples for each of Ar¹and Ar² are independently the same as the examples described in relationto the non-fused aromatic hydrocarbon group and the fused aromatichydrocarbon group. One of Ar¹ and Ar² may be a hydrogen atom.

M represents aluminum (Al), gallium (Ga) or indium (In), among which Inis preferable.

L in the formula (B1) represents a group represented by the followingformula (B2) or (B3).

In the formula (B2), R⁸ to R¹² independently represent a hydrogen atomor a hydrocarbon group having 1 to 40 carbon atoms. Adjacent groups mayform a cyclic structure. The hydrocarbon group may be substituted.

In the formula (B3), R¹³ to R²⁷ independently represent a hydrogen atomor a hydrocarbon group having 1 to 40 carbon atoms.

Adjacent groups may form a cyclic structure. The hydrocarbon group maybe substituted.

Examples of the hydrocarbon group having 1 to 40 carbon atomsrepresented by each of R⁸ to R¹² and R¹³ to R²⁷ in the formulae (B2) and(B3) are the same as those of R² to R⁷ in the formula (B1).

Examples of a divalent group for forming a cyclic structure betweenadjacent ones of groups R⁸ to R¹² and R¹³ to R²⁷ are a tetramethylenegroup, a pentamethylene group, a hexamethylene group, adiphenylmethane-2,2′-diyl group, a diphenylethane-3,3′-diyl group and adiphenylpropane-4,4′-diyl group.

The electron transporting layer preferably contains at least one ofnitrogen-containing heterocyclic derivatives respectively represented bythe following formulae (B4) to (B6).

In the formulae (B4) to (B6), R represents a hydrogen atom, an aromatichydrocarbon group having 6 to 60 ring carbon atoms, a fused aromatichydrocarbon group having 6 to 60 ring carbon atoms, a pyridyl group, aquinolyl group, an alkyl group having 1 to 20 carbon atoms or an alkoxygroup having 1 to 20 carbon atoms.

n is an integer of 0 to 4.

In the formulae (B4) to (B6), R¹ represents an aromatic hydrocarbongroup having 6 to 60 ring carbon atoms, a fused aromatic hydrocarbongroup having 6 to 60 ring carbon atoms, a pyridyl group, a quinolylgroup, an alkyl group having 1 to 20 carbon atoms or an alkoxy grouphaving 1 to 20 carbon atoms.

In the formulae (B4) to (B6), R² and R³ independently represent ahydrogen atom, an aromatic hydrocarbon group having 6 to 60 ring carbonatoms, a fused aromatic hydrocarbon group having 6 to 60 ring carbonatoms, a pyridyl group, a quinolyl group, an alkyl group having 1 to 20carbon atoms or an alkoxy group having 1 to 20 carbon atoms.

In the formulae (B4) to (B6), L represents an aromatic hydrocarbon grouphaving 6 to 60 ring carbon atoms, a fused aromatic hydrocarbon grouphaving 6 to 60 ring carbon atoms, a pyridinylene group or aquinolinylene group or a fluorenylene group.

In the formulae (B4) to (B6), Ar¹ represents an aromatic hydrocarbongroup having 6 to 60 ring carbon atoms, a fused aromatic hydrocarbongroup having 6 to 60 ring carbon atoms, a pyridinylene group or aquinolinylene group.

In the formulae (B4) to (B6), Ar² represents an aromatic hydrocarbongroup having 6 to 60 ring carbon atoms, a fused aromatic hydrocarbongroup having 6 to 60 ring carbon atoms, a pyridyl group, a quinolylgroup, an alkyl group having 1 to 20 carbon atoms or an alkoxy grouphaving 1 to 20 carbon atoms.

In the formulae (B4) to (B6), Ar³ represents an aromatic hydrocarbongroup having 6 to 60 ring carbon atoms, a fused aromatic hydrocarbongroup having 6 to 60 ring carbon atoms, a pyridyl group, a quinolylgroup, an alkyl group having 1 to 20 carbon atoms, an alkoxy grouphaving 1 to 20 carbon atoms or a group represented by —Ar¹—Ar² (in whichAr¹ and Ar² are the same as the above).

The aromatic hydrocarbon group, the fused aromatic hydrocarbon group,the pyridyl group, the quinolyl group, the alkyl group, the alkoxygroup, the pyridinylene group, the quinolinylene group and thefluorenylene group described in relation to the R, R¹, R², R³, L, Ar¹,Ar² and Ar³ in the formulae (B4) to (B6) may be substituted.

As an electron transport compound used for the electron injecting layeror the electron transporting layer, 8-hydroxyquinoline or a metalcomplex of its derivative, an oxadiazole derivative and anitrogen-containing heterocyclic derivative are preferable. An exampleof the 8-hydroxyquinoline or the metal complex of its derivative is ametal chelate oxinoid compound containing a chelate of oxine (typically8-quinolinol or 8-hydroxyquinoline). For instance, tris(8-quinolinol)aluminum can be used. Examples of the oxadiazole derivative are asfollows.

In the formulae representing the oxadiazole derivatives, Ar¹⁷, Ar¹⁸,Ar¹⁹, Ar²¹, Ar²² and Ar²⁵ are an aromatic hydrocarbon group having 6 to40 ring carbon atoms or a fused aromatic hydrocarbon group having 6 to40 ring carbon atoms.

The aromatic hydrocarbon group and the fused aromatic hydrocarbon groupmay be substituted. Ar¹⁷, Ar¹⁹ and Ar²² may be respectively the same asor different from Ar¹⁸, Ar²¹ and Ar²⁵.

Examples of the aromatic hydrocarbon group or the fused aromatichydrocarbon group are a phenyl group, a naphthyl group, a biphenylgroup, an anthranil group, a perylenyl group and a pyrenyl group.Examples of the substituent therefor are an alkyl group having 1 to 10carbon atoms, an alkoxy group having 1 to 10 carbon atoms and a cyanogroup.

In the formulae representing the oxadiazole derivatives, Ar²⁰, Ar²³ andAr²⁴ are a divalent aromatic hydrocarbon group having 6 to 40 ringcarbon atoms or a divalent fused aromatic hydrocarbon group having 6 to40 ring carbon atoms.

The aromatic hydrocarbon group and the fused aromatic hydrocarbon groupmay be substituted.

Ar²³ and Ar²⁴ may be mutually the same or different.

Examples of the divalent aromatic hydrocarbon group or the divalentfused aromatic hydrocarbon group are a phenylene group, a naphthylenegroup, a biphenylene group, an anthranylene group, a perylenylene groupand a pyrenylene group. Examples of the substituent therefor are analkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10carbon atoms and a cyano group.

Such an electron transport compound is preferably an electron transportcompound that can be favorably formed into a thin film(s). Examples ofthe electron transporting compounds are as follows.

The nitrogen-containing heterocyclic derivative as the electrontransport compound is exemplified by a nitrogen-containing heterocyclicderivative that is not a metal complex and is formed of an organiccompound represented by one of the following formulae. Examples of thenitrogen-containing heterocyclic derivative are a five-membered ring orsix-membered ring derivative having a skeleton represented by thefollowing formula (B7) and a derivative having a structure representedby the following formula (B8).

In the formula (B8), X represents a carbon atom or a nitrogen atom. Z₁and Z₂ each independently represent a group of atoms capable of forminga nitrogen-containing heterocycle.

More preferably, the nitrogen-containing heterocyclic derivative is anorganic compound having a nitrogen-containing aromatic polycyclic grouphaving a five-membered ring or six-membered ring. Further, when thenitrogen-containing heterocyclic derivative is such anitrogen-containing aromatic polycyclic group that contains pluralnitrogen atoms, the nitrogen-containing heterocyclic derivative ispreferably a nitrogen-containing aromatic polycyclic organic compoundhaving a skeleton formed by combining the skeletons respectivelyrepresented by the formulae (B7) and (B8), or by combining the skeletonsrespectively represented by the formulae (B7) and (B9).

A nitrogen-containing group of the nitrogen-containing aromaticpolycyclic organic compound is selected from nitrogen-containingheterocyclic groups respectively represented by, for instance, thefollowing formulae.

In the formulae representing the nitrogen-containing heterocyclicgroups, R represents an aromatic hydrocarbon group having 6 to 40 ringcarbon atoms, a fused aromatic hydrocarbon group having 6 to 40 ringcarbon atoms, an aromatic heterocyclic group having 2 to 40 ring carbonatoms, a fused aromatic heterocyclic group having 2 to 40 ring carbonatoms, an alkyl group having 1 to 20 carbon atoms or an alkoxy grouphaving 1 to 20 carbon atoms.

In the formulae representing the nitrogen-containing heterocyclic group,n is an integer of 0 to 5. When n is an integer of 2 or more, aplurality of R may be mutually the same or different.

A preferable specific compound is a nitrogen-containing heterocyclicderivative represented by the following formula (B10).HAr-L¹-Ar¹—Ar²  (B10)

In the formula (B10), HAr represents:

In the formula (B10), HAr represents a nitrogen-containing heterocyclicgroup having 1 to 40 ring carbon atom.

In the formula (B10), L¹ represents a single bond, an aromatichydrocarbon group having 6 to 40 ring carbon atoms, a fused aromatichydrocarbon group having 6 to 40 ring carbon atoms, an aromaticheterocyclic group having 2 to 40 ring carbon atoms or a fused aromaticheterocyclic group having 2 to 40 ring carbon atoms.

In the formula (B10), Ar¹ represents: a divalent aromatic hydrocarbongroup having 6 to 40 ring carbon atom.

In the formula (B10), Ar² represents an aromatic hydrocarbon grouphaving 6 to 40 ring carbon atoms, a fused aromatic hydrocarbon grouphaving 6 to 40 ring carbon atoms, an aromatic heterocyclic group having2 to 40 ring carbon atoms or a fused aromatic heterocyclic group having2 to 40 ring carbon atoms.

The nitrogen-containing heterocyclic group, the fused aromatichydrocarbon group, the fused aromatic hydrocarbon group, the aromaticheterocyclic group and the fused aromatic heterocyclic group describedin relation to HAr, L¹, Ar¹ and Ar² in the formula (B10) may besubstituted.

HAr in the formula (B10) is exemplarily selected from the followinggroup.

L¹ in the formula (B10) is exemplarily selected from the followinggroup.

Ar¹ in the formula (B10) is exemplarily selected from the followingarylanthranil group.

In the formulae representing the arylanthranil group, R¹ to R¹⁴independently represent a hydrogen atom, a halogen atom, an alkyl grouphaving 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbonatoms, an aryloxy group having 6 to 40 ring carbon atoms, an aromatichydrocarbon group having 6 to 40 ring carbon atoms, a fused aromatichydrocarbon group having 6 to 40 ring carbon atoms, an aromaticheterocyclic group having 2 to 40 ring carbon atoms or a fused aromaticheterocyclic group having 2 to 40 ring carbon atoms.

In the formulae representing the arylanthranil group, Ar³ represents anaromatic hydrocarbon group having 6 to 40 ring carbon atoms, a fusedaromatic hydrocarbon group having 6 to 40 ring carbon atoms, an aromaticheterocyclic group having 2 to 40 ring carbon atoms or a fused aromaticheterocyclic group having 2 to 40 ring carbon atoms.

The aromatic hydrocarbon group, the fused aromatic hydrocarbon group,the aromatic heterocyclic group and the fuse aromatic heterocyclic groupdescribed in relation to R¹ to R¹⁴ and Ar³ in the formulae of thearylanthranil group may be substituted.

The nitrogen-containing heterocyclic derivative may be anitrogen-containing heterocyclic derivative in which R¹ to R⁸ eachrepresent a hydrogen atom.

In the formulae of the arylanthranil group, Ar² is exemplarily selectedfrom the following group.

Other than the above, the following compound (see JP-A-9-3448) can befavorably used as the nitrogen-containing aromatic polycyclic organiccompound (i.e., the electron transport compound).

In the formula of the nitrogen-containing aromatic polycyclic organiccompound, R¹ to R⁴ independently represent a hydrogen atom, an aliphaticgroup, an alicyclic group, a carbocyclic aromatic cyclic group or aheterocyclic group. The aliphatic group, the alicyclic group, thecarbocyclic aromatic cyclic group and the heterocyclic group may besubstituted.

In the formula of the nitrogen-containing aromatic polycyclic organiccompound, X¹ and X² independently represent an oxygen atom, a sulfuratom or a dicyanomethylene group.

Alternatively, the following compound (see JP-A-2000-173774) can also befavorably used for the electron transporting compound.

In the formula, R¹, R², R³ and R⁴ are mutually the same or different andeach represent an aromatic hydrocarbon group or a fused aromatichydrocarbon group represented by the following formula.

In the formula, R⁵, R⁶, R⁷, R⁸ and R⁹ are mutually the same or differentand each represent a hydrogen atom, a saturated or unsaturated alkoxylgroup, alkyl group, amino group or alkylamino group. At least one of R⁵,R⁶, R⁷, R⁸ and R⁹ represents a saturated or unsaturated alkoxyl group,alkyl group, amino group or alkylamino group.

The electron transport compound may be a polymer compound containing thenitrogen-containing heterocyclic group or the nitrogen-containingheterocyclic derivative.

The electron injecting layer preferably contains an insulator or asemiconductor as an inorganic compound in addition to thenitrogen-containing cyclic derivative. Such an insulator or asemiconductor, when contained in the electron injecting layer, caneffectively prevent a current leak, thereby enhancing electroncapability of the electron injecting layer.

It is also preferable that the electron injecting layer according tothis exemplary embodiment contains a reduction-causing dopant.

Film Thickness

In the organic EL device of this exemplary embodiment, a thickness ofeach layer between the anode and the cathode is not particularly limitedexcept for a thickness of each of the above-mentioned layers to beparticularly defined. However, the thickness of each of the emittinglayer and the like is typically preferably in a range from severalnanometers to 1 μm because an excessively-thinned film is likely toentail defects such as a pin hole while an excessively-thickened filmrequires application of high voltage and deteriorates efficiency.

Manufacturing Method of Organic EL Device

A manufacturing method of the organic EL device of the invention issubject to no limitation. Any typical manufacturing method of theorganic EL device is usable. Specifically, each layer is formable byvacuum deposition, a casting method, a coating method and a spin coatingmethod. Moreover, in addition to the casting method, the coating methodand the spin coating using a solution, in which the organic material ofthe layers are dispersed, on a transparent polymer such aspolycarbonate, polyurethane, polystyrene, polyarylate and polyester, therespective layers can be formed by simultaneous deposition with theorganic material and the transparent polymer.

Second Exemplary Embodiment

Next, a second exemplary embodiment is described below.

In the description of the second exemplary embodiment, the samecomponents as those in the first exemplary embodiment are denoted by thesame reference signs and names to simplify or omit an explanation of thecomponents. In the second exemplary embodiment, the same materials andcompounds as described in the first exemplary embodiment are usable.

An organic EL device 1A according to the second exemplary embodiment isdifferent from that of the first exemplary embodiment in that anemitting unit 5A, a third emitting layer 53 and a spacing layer 8between the emitting unit 5A and the third emitting layer 53 areprovided. As shown in FIG. 2, the anode, 3, the hole transporting layer6, the emitting unit 5A, the spacing layer 8, the third emitting layer53, the electron transporting layer 7 and the cathode 4 are sequentiallylaminated on the substrate 2.

The emitting unit 5A includes a first emitting layer 51 continuouslyformed to the hole transporting layer 6 and a second emitting layer 52continuously formed between the first emitting layer 51 and the spacinglayer 8.

The first emitting layer 51 contains a host material and a luminescentmaterial. The host material is preferably an amine derivative such as amonoamine compound, a diamine compound, a triamine compound, a tetraminecompound and an amine compound substituted by a carbazole group. Thehost material may be the same material as the first host materialrepresented by the formula (1) and the second host material representedby the formula (2). The luminescent material preferably exhibits anemission peak of 570 nm or more. The emission peak of 570 nm or more isshown by, for instance, red emission.

The second emitting layer 52 is the emitting layer according to theinvention. In other words, the second emitting layer 52 functions thesame as the emitting layer 5 of the first exemplary embodiment.

Provided as an energy barrier of a HOMO level or a LUMO level betweenthe second emitting layer 52 and the third emitting layer 53 adjacentthereto, the spacing layer 8 controls injection of charge (holes orelectrons) into the second emitting layer 52 and the third emittinglayer 53 and controls balance of charge injected thereinto. Moreover,the spacing layer 8 is provided as a barrier of triplet energy, therebypreventing diffusion of triplet energy generated in the second emittinglayer 52 to the third emitting layer 53 and providing efficient emissionwithin the second emitting layer 52.

The third emitting layer 53 is, for instance, a blue fluorescentemitting layer having a peak wavelength of 450 nm to 500 nm. The thirdemitting layer 53 contains the third host material and the thirdluminescent material.

Examples of the third host material are a compound having a centralanthracene skeleton which is represented by the following formula (41).

In the formula (41), Ar₄₁ and Ar₄₂ each are a group induced from asubstituted or unsubstituted aromatic ring having 6 to 20 ring carbonatoms.

R₄₁ to R₄₈ each are a hydrogen atom, a substituted or unsubstituted arylgroup having 6 to 50 ring carbon atoms, a substituted or unsubstitutedheteroaryl group having 5 to 50 atoms for forming a ring (hereinafterreferred to as ring atoms), a substituted or unsubstituted alkyl grouphaving 1 to 50 carbon atoms, a substituted or unsubstituted cycloalkylgroup having 3 to 50 carbon atoms, a substituted or unsubstituted alkoxygroup having 1 to 50 carbon atoms, a substituted or unsubstitutedaralkyl group having 6 to 50 carbon atoms, a substituted orunsubstituted aryloxy group having 5 to 50 ring atoms, a substituted orunsubstituted arylthio group having 5 to 50 ring atoms, a substituted orunsubstituted alkoxycarbonyl group having 1 to 50 carbon atoms, asubstituted or unsubstituted silyl group, a carboxyl group, a halogenatom, a cyano group, a nitro group or a hydroxy group.

Examples of a substituent for the aromatic ring of each of Ar₄₁ and Ar₄₂are a substituted or unsubstituted aryl group having 6 to 50 ring carbonatoms, a substituted or unsubstituted alkyl group having 1 to 50 carbonatoms, a substituted or unsubstituted cycloalkyl group having 3 to 50carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 50carbon atoms, a substituted or unsubstituted aralkyl group having 6 to50 carbon atoms, a substituted or unsubstituted aryloxy group having 5to 50 ring atoms, a substituted or unsubstituted arylthio group having 5to 50 ring atoms, a substituted or unsubstituted alkoxycarbonyl grouphaving 1 to 50 carbon atoms, a substituted or unsubstituted silyl group,a carboxyl group, a halogen atom, a cyano group, a nitro group or ahydroxy group.

Examples of the third luminescent material are an arylamine compound, astyrylamine compound, anthracene, naphthalene, phenanthrene, pyrene,tetracene, coronene, chrysene, fluorescein, perylene, phthaloperylene,naphthaloperylene, perynone, phthaloperynone, naphthaloperynone,diphenylbutadiene, tetraphenylbutadiene, coumaline, oxadiazole,aldazine, bisbenzoxazoline, bisstyryl, pyrazine, cyclopentadiene, ametal complex of quinoline, a metal complex of aminoquinoline, a metalcomplex of benzoquinoline, imine, diphenylethylene, vinylanthracene,diaminocarbazole, pyrane, thiopyrane, polymethine, merocyanin, animidazole chelated oxinoid compound, quinacridone, rubrene and afluorescent dye.

The third emitting layer 53 is, for instance, a blue fluorescentemitting layer having a peak wavelength of 450 nm to 500 nm.

Since the organic EL device 1A includes the first emitting layer 51exhibiting red emission, the second emitting layer 52 exhibiting greenemission and the third emitting layer 53 exhibiting blue emission, theorganic EL device 1A can exhibit white emission as a whole.

Accordingly, the organic EL device 1A is suitably applicable as asurface light source for lighting, a backlight and the like.

Third Exemplary Embodiment

Next, a third exemplary embodiment is described below.

In the description of the third exemplary embodiment, the samecomponents as those in the first exemplary embodiment are denoted by thesame reference signs and names to simplify or omit an explanation of thecomponents. In the third exemplary embodiment, the same materials andcompounds as described in the first exemplary embodiment are usable.

The organic EL device according to the third exemplary embodiment is aso-called tandem-type device including a charge generating layer and twoor more emitting units. In addition to charges injected from a pair ofelectrodes, charges supplied from the charge generating layer areinjected into the emitting unit. Accordingly, by providing the chargegenerating layer, luminous efficiency (current efficiency) relative toinjected current is improved.

As shown in FIG. 3, an organic EL device 1B according to the thirdexemplary embodiment is configured to include the anode 3, the holetransporting layer 6, the first emitting unit 5A, the electrontransporting layer 7, a charge generating layer 9, a second holetransporting layer 6B, a second emitting unit 5B, a second electrontransporting layer 7B and the cathode 4 sequentially laminated on thesubstrate 2.

The first emitting unit 5A functions the same as the first emitting unitof the second exemplary embodiment. The second emitting layer 52 formingthe first emitting unit 5A is the emitting layer of the invention. Inother words, the first emitting unit 5A functions the same as theemitting layer 5 of the first exemplary embodiment and the secondemitting layer of the second exemplary embodiment.

The second emitting unit 5B includes the third emitting layer 53continuously formed to the second hole transporting layer 6B and thefourth emitting layer 54 continuously formed between the third emittinglayer 53 and the second electron transporting layer 7B.

The third emitting layer 53 functions the same as the third emittinglayer of the second exemplary embodiment.

The fourth emitting layer 54 is a green fluorescent emitting layerhaving a peak wavelength of about 500 nm to 570 nm. The fourth emittinglayer 54 contains the fourth host material and the fourth luminescentmaterial.

The charge generating layer 9 in which charges are generated when anelectrical field is applied injects electrons into the electrontransporting layer 7 and injects holes into the second hole transportinglayer 6B.

As a material for the charge generating layer 9, known materials such asthe materials described in the specification of U.S. Pat. No. 7,358,661are usable. Specifically, examples of the material for the chargegenerating layer 9 are metal oxides, nitrides, iodides, borides and thelike of In, Sn, Zn, Ti, Zr, Hf, V, Mo, Cu, Ga, Sr, La, Ru and the like.The electron transporting zone 7 near an interface with the chargegenerating layer is preferably doped with a donor (e.g., an alkalimetal) in order that the third emitting layer 53 can easily acceptelectrons from the charge generating layer 9. As the donor, at least oneof a donor metal, a donor metal compound and a donor metal complex canbe used. Examples of the compounds usable for the donor metal, the donormetal compound and the donor metal complex are compounds disclosed inInternational Publication No. 2010/134352.

The second hole transporting layer 6B and the second electrontransporting layer 7B function the same as the hole transporting layerand the electron transporting layer of the first exemplary embodiment.

Since the organic EL device 1B is a so-called tandem-type device,electrical current for driving can be reduced and durability can beimproved.

Fourth Exemplary Embodiment

An organic EL device 1C according to a fourth exemplary embodiment isdifferent from that of the second exemplary embodiment in that the firstemitting layer 51 is not provided.

In the description of the fourth exemplary embodiment, the samecomponents as those in the second exemplary embodiments are denoted bythe same reference signs and names to simplify or omit an explanation ofthe components. In the fourth exemplary embodiment, the same materialsand compounds as described in the second exemplary embodiments areusable.

As shown in FIG. 4, the organic EL device 1C according to the fourthexemplary embodiment is configured to include the anode 3, the holetransporting layer 6, the second emitting layer 52, the spacing layer 8,the third emitting layer 53, the electron transporting layer 7 and thecathode 4 sequentially laminated on the substrate 2.

The second emitting layer 52 is the emitting layer according to theinvention. In other words, the second emitting layer 52 functions thesame as the emitting layer 5 of the first exemplary embodiment.

The third emitting layer 53 is, for instance, a blue fluorescentemitting layer having a peak wavelength of 450 nm to 500 nm. The thirdemitting layer 53 contains the third host material and the thirdluminescent material.

When a dopant material exhibiting yellow emission is used as the secondemitting layer 52 in the organic EL device 1C, since the organic ELdevice 1C includes the second emitting layer 52 exhibiting yellowemission and the third emitting layer 53 exhibiting blue emission, theorganic EL device 1C can exhibit white emission as a whole. Typically,white emission of the entire device requires three layers respectivelyexhibiting red emission, green emission and blue emission to exhibitemission in good balance. However, in this exemplary embodiment, thelayers exhibiting red emission and green emission can be replaced byonly the second emitting layer 52 exhibiting yellow emission.Accordingly, the organic EL device 1A is suitably applicable as asurface light source for lighting, a backlight and the like.

Fifth Exemplary Embodiment

An organic EL device 1D according to a fifth exemplary embodiment isdifferent from that of the third exemplary embodiment in that the firstemitting layer 51 is not provided.

In the description of the fifth exemplary embodiment, the samecomponents as those in the third exemplary embodiments are denoted bythe same reference signs and names to simplify or omit an explanation ofthe components. In the fifth exemplary embodiment, the same materialsand compounds as described in the third exemplary embodiments areusable.

As shown in FIG. 5, the organic EL device 1D of the fifth exemplaryembodiment is configured to include the anode 3, the hole transportinglayer 6, the second emitting layer 52, the electron transporting layer7, the charge generating layer 9, the second hole transporting layer 6B,the second emitting unit 5B, the second electron transporting layer 7Band the cathode 4 sequentially laminated on the substrate 2.

The second emitting layer 52 is the emitting layer of the invention. Inother words, the second emitting layer 52 functions the same as theemitting layer 5 of the first exemplary embodiment and the secondemitting layer of the third exemplary embodiment.

The second emitting unit 5B includes the third emitting layer 53continuously formed to the second hole transporting layer 6B and thefourth emitting layer 54 continuously formed between the third emittinglayer 53 and the second electron transporting layer 7B.

The third emitting layer 53 functions the same as the third emittinglayer of the second exemplary embodiment.

The fourth emitting layer 54 is a green fluorescent emitting layerhaving a peak wavelength of about 500 nm to 570 nm. The fourth emittinglayer 54 contains the fourth host material and the fourth luminescentmaterial.

Since the organic EL device 1D is a so-called tandem-type device,electrical current for driving can be reduced and durability can beimproved.

Sixth Exemplary Embodiment

Next, a sixth exemplary embodiment will be described below.

In the sixth exemplary embodiment, a material for an organic EL device(an organic-EL-device material) used for manufacturing the organic ELdevice according to the above exemplary embodiments will be describedbelow.

The organic-EL-device material contains a compound represented by theformula (1) and a compound represented by the formula (2). It should notbe excluded that the organic-EL-device material contains othermaterial(s).

In the organic-EL-device material, the compound represented by theformula (1) is preferably a compound represented by the formula (3).

In the organic-EL-device material, the compound represented by theformula (1) is also preferably a compound represented by the formula (4)or (5).

Further, in the organic-EL-device material, the compound represented bythe formula (2) in which FA is preferably a substituted or unsubstitutedfused aromatic cyclic group having 2 to 5 fused rings, or a substitutedor unsubstituted fused aromatic heterocyclic group having 2 to 5 fusedrings.

Furthermore, FA is preferably represented by the formula (2-A), morepreferably represented by any one of the formulae (2-1) to (2-4).Particularly preferably, FA is represented by the formula (2-1) or(2-2).

Herein, when a total mass percentage of the first and second hostmaterials contained in the organic-EL-device material is 100 mass %, thefirst host material is preferably set in a range of 10 mass % to 90 mass% and the second host material is preferably set in a range of 10 mass %to 90 mass %. More preferably, the first host material is set in a rangeof 40 mass % to 60 mass % and the second host material is set in a rangeof 40 mass % to 60 mass %.

Since the organic-EL-device material according to the sixth exemplaryembodiment contains the compound represented by the formula (1) (thefirst host material) and the compound represented by the formula (2)(the second host material), the organic-EL-device material is preferablyused for forming the emitting layer of the organic EL devices accordingto the above exemplary embodiments. The organic-EL-device material maybe used for a layer other than the emitting layer forming the organic ELdevice.

When the organic-EL-device material is used for the emitting layer, theorganic-EL-device material may contain a phosphorescent dopant materialin addition to the compound represented by the formula (1) and thecompound represented by the formula (2).

When the organic-EL-device material according to the sixth exemplaryembodiment is used for manufacturing an organic EL device, since thecompound represented by the formula (1) and the compound represented bythe formula (2) are mixed in advance, there is no need to mix thosecompounds while adjusting a mass ratio therebetween, which facilitatesmanufacturing the organic EL device. Moreover, for instance, when theorganic-EL-device material is used for forming the emitting layer byvacuum deposition, with a proviso that deposition temperatures of thefirst and second host materials are approximate to each other, there isno need to prepare an evaporation boat for each of the first and secondhost materials, which simplifies a manufacturing device.

Modification(s) of Embodiment(s)

It should be noted that the invention is not limited to the abovedescription but may include any modification as long as suchmodification stays within a scope and a spirit of the invention.

In the first and second exemplary embodiments, the anode and the holetransporting layer are continuously formed. However, the hole injectinglayer may be further provided between the anode and the holetransporting layer.

Preferable examples of a material of the hole injecting layer are aporphyrin compound, an aromatic tertiary amine compound, or astyrylamine compound. Particularly preferable examples include anaromatic tertiary amine compound such as hexacyanohexaazatriphenylene(HAT).

In the first to third exemplary embodiments, the cathode and theelectron transporting layer are continuously formed to each other.However, the electron injecting layer may be further formed between thecathode and the electron transporting layer.

Although two emitting units are formed in the third exemplaryembodiments, three or more emitting units may be formed.

EXAMPLES

The invention will be described in more detail below by exemplifyingexamples and comparatives. It should be noted that the invention is notlimited to specific description of the examples and the like.

Synthesis Example 1 (Synthesis of Compound GH1-1)

3-bromobenzaldehydo (100 g, 54 mmol) and aniline (50 g, 54 mmol) wereadded to toluene (1 L) and refluxed for 8 hours. After the reactionsolution was cooled down, a solvent was concentrated under reducedpressure to obtain an intermediate 1-1 (130 g, a yield of 93%).

Subsequently, under an argon gas atmosphere, the intermediate body 1-1(130 g, 50 mmol), benzamidine hydrochloride (152 g, 100 mmol), anhydrousethanol (1 L), and sodium hydroxide (42 g) were added together insequential order, and stirred at 80 degrees C. for 16 hours.Subsequently, sodium-t-butoxide (20 g, 208 mmol) were further added andheated at 80 degrees C. for 16 hours with stirring. After the reactionsolution was cooled down to the room temperature, a solid was separatedby filtration and washed with methanol to obtain an intermediate 1-2 (67g, a yield of 37%).

Under an argon gas atmosphere, an intermediate 1-3 (1.6 g, 3.9 mmol),the intermediate 1-2 (1.5 g, 3.9 mmol),tris(dibenzylideneacetone)dipalladium (0.071 g, 0.078 mmol),tri-t-butylphosphonium tetrafluoroborate (0.091 g, 0.31 mmol), sodiumt-butoxide (0.53 g, 5.5 mmol), and anhydrous toluene (20 mL) weresequentially mixed, and refluxed for 8 hours.

After the reaction solution was cooled down to the room temperature, anorganic phase was removed and an organic solvent was distilled awayunder reduced pressure. The obtained residue was refined by silica-gelcolumn chromatography, so that a compound GH-1 (2.3 g, a yield of 82%)was obtained.

As a result of FD-MS analysis, m/e was equal to 715 while a calculatedmolecular weight was 715.

Synthesis Example 2 (Synthesis of Compound GH2-1)

Under an argon gas atmosphere, to a three-necked flask, an intermediatebody 2-2 (2.5 g, 8.1 mmol), an intermediate 2-1 (3 g, 7.3 mmol),Pd₂(dba)₃ (0.14 g, 0.15 mmol), P(tBu)₃HBF4 (0.17 g, 0.6 mmol), sodiumt-butoxide (1.1 g, 11 mmol), and anhydrous xylene (30 mL) weresequentially added, and refluxed for 8 hours.

Water was added to the reaction solution to precipitate solid. Then, theobtained solid was washed with hexane, followed by methanol. Theobtained solid was then refined by silica-gel column chromatography, sothat a compound GH2-1 (3.7 g, a yield of 80%) is obtained.

As a result of FD-MS analysis, m/e was equal to 634 while a calculatedmolecular weight was 634.

Synthesis Example 3 (Synthesis of Compound GH2-2)

Under an argon gas atmosphere, 9-phenanthreneboronic acid (2.7 g, 12.2mmol), p-bromoiodobenzene (3.4 g, 12.2 mmol),tetrakis(triphenylphosphine)palladium (0.26 g, 0.24 mmol), and anaqueous solution of 2M sodium carbonate (20 mL) were added to toluene(40 mL), and heated at 80 degrees C. for 8 hours with stirring.

After the organic phase was separated and condensed with an evaporator,the obtained residue was refined by silica-gel column chromatography,whereby an intermediate 3-1 (3.0 g, a yield of 75%) was obtained.

Under an argon gas atmosphere, to a three-necked flask, an intermediate1-3 (3.3 g, 8.1 mmol), an intermediate GH3-1 (2.4 g, 7.3 mmol),Pd₂(dba)₃ (0.14 g, 0.15 mmol), P(tBu)₃HBF4 (0.17 g, 0.6 mmol), sodiumt-butoxide (1.1 g, 11 mmol), and anhydrous xylene (30 mL) weresequentially added, and refluxed for 8 hours.

Water was added to the reaction solution to precipitate solid. Then, theobtained solid was washed with hexane, followed by methanol. Theobtained solid was then refined by silica-gel column chromatography,thereby obtaining a compound GH2-2 (3.3 g, a yield of 68%).

As a result of FD-MS analysis, m/e was equal to 660 while a calculatedmolecular weight was 660.

Synthesis Example 4 (Synthesis of Compound GH2-3)

Synthesis of Intermediate Body 4-1

Under an argon gas atmosphere, toluene (150 mL), dimethoxyethane (150mL) and an aqueous solution of 2M sodium carbonate (150 mL) were addedto 4-bromoiodebenzene (28.3 g, 100.0 mmol), dibenzofuran-4-boronic acid(22.3 g, 105 mmol), tetrakis(triphenylphosphine)palladium(0) (2.31 g,2.00 mmol), and were refluxed for 10 hours.

After the reaction was over, the mixture was separated by filtration.The obtained aqueous phase thereof was removed. After an organic phasethereof was dried with sodium sulfate, the mixture was condensed.Residue thereof was refined by silica-gel column chromatography, so thatan intermediate 4-1 (26.2 g, a yield of 81%) was obtained.

As a result of FD-MS analysis, m/e was equal to 322 while a calculatedmolecular weight was 322.

Synthesis of GH2-3

Under an argon gas atmosphere, to a three-necked flask, the intermediate4-1 (2.36 g, 7.3 mmol), the intermediate 2-1 (3.0 g, 7.3 mmol), CuI (1.4g, 7.3 mmol), tripotassium phosphate (2.3 g, 11 mmol), anhydrous dioxane(30 mL) and cyclohexane diamine (0.84 g, 7.3 mmol) were added togetherin sequential order, and stirred at 100 degrees C. for 8 hours.

Water was added to the reaction solution to precipitate solid. Then, theobtained solid was washed with hexane, followed by methanol. Theobtained solid was then refined by silica-gel column chromatography,thereby obtaining a compound GH2-3 (2.9 g, a yield of 60%).

As a result of FD-MS analysis, m/e was equal to 650 while a calculatedmolecular weight was 650.

Synthesis Example 5 (Synthesis of Compound GH2-4)

Under an argon gas atmosphere, to a three-necked flask, an intermediate5-1 (2.1 g, 8.1 mmol), the intermediate 2-1 (3 g, 7.3 mmol), Pd₂(dba)₃(0.14 g, 0.15 mmol), P(tBu)₃HBF4 (0.17 g, 0.6 mmol), sodium t-butoxide(1.1 g, 11 mmol), and anhydrous xylene (30 mL) were sequentially added,and refluxed for 8 hours.

Water was added to the reaction solution to precipitate solid. Then, theobtained solid was washed with hexane, followed by methanol. Theobtained solid was then refined by silica-gel column chromatography, sothat a compound GH2-4 (2.8 g, a yield of 65%) is obtained.

As a result of FD-MS analysis, m/e was equal to 590 while a calculatedmolecular weight was 590.

Example 1

In Example 1, an organic EL device was manufactured as follows.

A glass substrate (size: 25 mm×75 mm×1.1 mm thick, manufactured byGeomatec Co., Ltd.) having an ITO transparent electrode (anode) wasultrasonic-cleaned in isopropyl alcohol for five minutes, and thenUV/ozone-cleaned for 30 minutes.

After the glass substrate having the transparent electrode line wascleaned, the glass substrate was mounted on a substrate holder of avacuum deposition apparatus. A compound HA-1 was deposited on a surfaceof the glass substrate where the transparent electrode line was providedin a manner to cover the transparent electrode, thereby forming a 5-nmthick HA-1 film. The HA-1 film serves as a hole injecting layer.

A compound HT-1 was deposited on the HA-1 film to form a 65-nm thickHT-1 film. The HT-1 film serves as the first hole transporting layer.

Next, a compound HT-2 was deposited on the HT-1 film to form a 10-nmthick HT-2 film. The HT-2 film serves as the second hole transportinglayer.

The compound GH1-1 (the first host material), the compound GH2-1 (thesecond host material) and Ir(bzq)₃ (the phosphorescent dopant material)were co-deposited on the second hole transporting layer. Thus, a 25-nmthick emitting layer exhibiting yellow emission was formed. Theconcentration of each of the second host material and the phosphorescentdopant material was set at 10 mass %. The first host material accountedfor the rest.

A compound ET-1 was deposited on the hole blocking layer to form a 35-nmthick first electron transporting layer.

A compound ET-2 was deposited on the first electron transporting layerto form a 30-nm thick second electron transporting layer. LiF wasdeposited at a rate of 1 Å/min on the electron transporting layer toform a 1-nm electron injecting cathode. A metal Al was deposited on theelectron injecting cathode to form an 80-nm thick cathode.

Comparative 1

An organic EL device was manufactured in the same manner as Example 1,except that the compound GH2-1 (the second host material) was not used.

Table 1 shows the device arrangement of Example 1 and ComparativeExample 1. The numerals without unit in parentheses in Table 1 indicatea thickness of each layer (unit: nm). The numerals with % indicate amass % concentration of the compounds. With respect to the emittinglayer, the mass % concentration of each of the second host material andthe phosphorescent dopant material is indicated, but description of theconcentration of the first host material is omitted.

Evaluation of Organic EL Device

The prepared organic EL devices were evaluated in terms of drivevoltage, external quantum efficiency EQE and lifetime. The currentdensity was set at 10.00 mA/cm² on each evaluation item. The results areshown in Table 2.

Drive Voltage

Voltage was applied between ITO and Al such that a current density was1.00 mA/cm² or 10.00 mA/cm², where the voltage (unit: V) was measured.

External Quantum Efficiency EQE

The external quantum efficiency EQE (unit: %) was calculated from theobtained spectral-radiance spectrum, assuming that Lambertian radiationwas carried out.

Lifetime

Time (LT90) elapsed before the luminance intensity was decreased to 90%was obtained based on the initial luminance intensity 10,000 nit(cd/m²).

Examples 2 to 7

In Examples 2 to 7, the organic EL devices were formed in the samemanner as in Example 1 except that the materials used in Example 1 werereplaced as shown in Table 2.

Compounds used in Examples 1 to 7 and Comparative Example 1 are shownbelow. In Examples 1 to 7, the compounds GH1-1, GH1-2 and GH1-3contained in the emitting layer are the first host material of theinvention and the compounds GH2-1, GH2-2, GH2-3 and GH2-4 are the secondhost material of the invention.

These organic EL devices were evaluated in the same manner as in Example1 and Comparative Example 1. The results are shown in Table 2.

TABLE 1 Device Arrangement Example 1ITO(75)/HA-1(5)/HT-1(65)/HT-2(10)/GH1-1:GH2- 1:Ir(bzq)3(25,10%:10%)/ET-1(35)/ET-2(30)/LiF(1)/Al(80) Comp. 1ITO(75)/HA-1(5)/HT-1(65)/HT-2(10)/GH1- 1:Ir(bzq)3(25,10%)/ET-1(35)/ET-2(30)/LiF(1)/Al(80)

TABLE 2 First Second Currnet Drive LT90 Host Host Density Voltage EQE @10000 nit Material Material (mA/cm²) (V) (%) (hrs) Example 1 GH1-1 GH2-110 3.45 20.8 1200 Example 2 GH1-1 GH2-2 10 3.64 20.8 500 Example 3 GH1-1GH2-3 10 3.23 21.8 900 Example 4 GH1-1 GH2-4 10 3.27 23.1 800 Example 5GH1-2 GH2-3 10 3.34 20.9 200 Example 6 GH1-3 GH2-3 10 3.29 22.0 200Example 7 GH1-3 GH2-4 10 3.32 21.8 150 Comp. 1 GH1-1 — 10 3.40 20.5 100

It is understood from Table 2 that the organic EL device of each ofExamples has a longer lifetime than a lifetime of the organic EL deviceof Comparative Example while keeping a high efficiency.

The invention claimed is:
 1. An organic electroluminescence device,comprising: an anode; a cathode; and at least an emitting layer betweenthe anode and the cathode, the emitting layer comprising: a first hostmaterial; a second host material; and a phosphorescent dopant material,wherein the first host material is a compound represented by a formula(3):

and the second host material is a compound represented by a formula (2):

where: Z¹ represents a cyclic structure fused at a of the formula (3)and is represented by a formula (1-1):

Z² represents a cyclic structure fused at b of the formula (3) and isrepresented by a formula (1-2); L¹ represents a single bond; m is 1; nis 2; c, d, e, f are fused at a or b in the formula (3); R¹¹ and R³¹each represent a hydrogen atom; three X¹ are nitrogen atoms; R¹ eachindependently represent an unsubstituted phenyl group or anunsubstituted biphenyl group; a plurality of R¹ are mutually the same ordifferent; X³ is N—R³²; R³² represents an unsubstituted phenyl group; R²independently represents a hydrogen atom, a halogen atom, a cyano group,a substituted or unsubstituted aryl group having 6 to 30 ring carbonatoms, a substituted or unsubstituted heterocyclic group having 5 to 30ring atoms, a substituted or unsubstituted alkyl group having 1 to 30carbon atoms, a substituted or unsubstituted alkenyl group having 2 to30 carbon atoms, a substituted or unsubstituted alkynyl group having 2to 30 carbon atoms, a substituted or unsubstituted alkylsilyl grouphaving 3 to 30 carbon atoms, a substituted or unsubstituted arylsilylgroup having 6 to 30 ring carbon atoms, a substituted or unsubstitutedalkoxy group having 1 to 30 carbon atoms, a substituted or unsubstitutedaralkyl group having 6 to 30 ring carbon atoms, or a substituted orunsubstituted aryloxy group having 6 to 30 ring carbon atoms; at leastone of R² at 2-position, 3-position, 4-position, 5-position, 6-position,and 7-position represents a substituted or unsubstituted 1-carbazolylgroup, a substituted or unsubstituted 2-carbazolyl group, a substitutedor unsubstituted 3-carbazolyl group, or a substituted or unsubstituted4-carbazolyl group; R² at 1-position and 8-position do not represent asubstituted or unsubstituted carbazolyl group; p and q are 4; aplurality of R² are mutually the same or different; adjacent groups ofR² are optionally bonded with each other to form a ring; L² represents asingle bond or a linking group, the linking group being one or acombination of a substituted or unsubstituted arylene group having 6 to30 ring carbon atoms, a substituted or unsubstituted heterocyclic grouphaving 5 to 30 ring atoms, and a cycloalkylene group having 5 to 30 ringcarbon atoms; and FA represents a substituted or unsubstituted fusedaromatic cyclic group having 10 to 30 ring carbon atoms.
 2. The organicelectroluminescence device according to claim 1, wherein the second hostmaterial is represented by the formula (2) in which FA is a substitutedor unsubstituted fused aromatic cyclic group having 2 to 5 fused rings.3. The organic electroluminescence device according to claim 1, whereinthe second host material is represented by the formula (2) in which FAis represented by a formula (2-A) below,

where: Y represents C(R²¹)₂; R² and R²¹ represent the same as R² of theformula (2); one of R² is a single bond to be bonded with L² in theformula (2); a plurality of R²¹ are mutually the same or different; andr and s are
 4. 4. The organic electroluminescence device according toclaim 1, wherein: the second host material is represented by the formula(2) in which FA is represented by formula (2-4):

where: R² and R²¹ represent the same as R² of the formula (2); one of R²is a single bond to be bonded with L² in the formula (2); and r and sare
 4. 5. The organic electroluminescence device according to claim 1,wherein an emission peak wavelength of the phosphorescent dopantmaterial is in a range of 490 nm to 700 nm.
 6. A material for an organicelectroluminescence device, comprising a compound represented by aformula (3) and a compound represented by a formula (2):

where: Z¹ represents a cyclic structure fused at a of the formula (3)and is represented by a formula (1-1):

Z² represents a cyclic structure fused at b of the formula (3) and isrepresented by a formula (1-2); L¹ represents a single bond m is 1; n is2; c, d, e, f are fused at a or b in the formula (3); R¹¹ and R³¹ eachrepresent a hydrogen atom; three X¹ are nitrogen atoms; R¹ eachindependently represent an unsubstituted phenyl group or anunsubstituted biphenyl group; a plurality of R¹ are mutually the same ordifferent; X³ is N—R³²; R³² represents an unsubstituted phenyl group; R²independently represents a hydrogen atom, a halogen atom, a cyano group,a substituted or unsubstituted aryl group having 6 to 30 ring carbonatoms, a substituted or unsubstituted heterocyclic group having 5 to 30ring atoms, a substituted or unsubstituted alkyl group having 1 to 30carbon atoms, a substituted or unsubstituted alkenyl group having 2 to30 carbon atoms, a substituted or unsubstituted alkynyl group having 2to 30 carbon atoms, a substituted or unsubstituted alkylsilyl grouphaving 3 to 30 carbon atoms, a substituted or unsubstituted arylsilylgroup having 6 to 30 ring carbon atoms, a substituted or unsubstitutedalkoxy group having 1 to 30 carbon atoms, a substituted or unsubstitutedaralkyl group having 6 to 30 ring carbon atoms, or a substituted orunsubstituted aryloxy group having 6 to 30 ring carbon atoms; at leastone of R² at 2-position, 3-position, 4-position, 5-position, 6-position,and 7-position represents a substituted or unsubstituted 1-carbazolylgroup, a substituted or unsubstituted 2-carbazolyl group, a substitutedor unsubstituted 3-carbazolyl group, or a substituted or unsubstituted4-carbazolyl group; R² at 1-position and 8-position do not represent asubstituted or unsubstituted carbazolyl group; p and q are 4; aplurality of R² are mutually the same or different; L² represents asingle bond or a linking group, the linking group being one or acombination of a substituted or unsubstituted arylene group having 6 to30 ring carbon atoms, a substituted or unsubstituted heterocyclic grouphaving 5 to 30 ring atoms, and a cycloalkylene group having 5 to 30 ringcarbon atoms; adjacent groups of R² are optionally bonded with eachother to form a ring; and FA represents a substituted or unsubstitutedfused aromatic cyclic group having 10 to 30 ring carbon atoms.
 7. Thematerial for the organic electroluminescence device according to claim6, wherein FA in the formula (2) is a substituted or unsubstituted fusedaromatic cyclic group having 2 to 5 fused rings.
 8. The material for theorganic electroluminescence device according to claim 6, wherein: FA inthe formula (2) is represented by a formula (2-A):

where: Y represents C(R²¹)₂; R² and R²¹ represent the same as R² of theformula (2); one of R² is a single bond to be bonded with L² in theformula (2); a plurality of R²¹ are mutually the same or different; andr and s are
 4. 9. The material for the organic electroluminescencedevice according to claim 6, wherein: FA in the formula (2) isrepresented by a formula (2-4):

where: R² and R²¹ represent the same as R² of the formula (2); one of R²is a single bond to be bonded with L² in the formula (2); and r and sare
 4. 10. The organic electroluminescence device according to claim 1,wherein: L² represents a single bond or an unsubstituted arylene grouphaving 6 to 30 ring carbon atoms; at least one of R² at 2-position,3-position, 4-position, 5-position, 6-position, and 7-positionrepresents a substituted or unsubstituted 1-carbazolyl group, asubstituted or unsubstituted 2-carbazolyl group, a substituted orunsubstituted 3-carbazolyl group, or a substituted or unsubstituted4-carbazolyl group; R² at 1-position and 8-position represent a hydrogenatom; the rest of R² each independently represent a hydrogen atom, anunsubstituted aryl group having 6 to 30 ring carbon atoms, or anunsubstituted alkyl group having 1 to 30 carbon atoms; and FA representsan unsubstituted fused aromatic cyclic group having 10 to 30 ring carbonatoms.
 11. The organic electroluminescence device according to claim 1,wherein: L² represents a single bond or an unsubstituted phenylenegroup; at least one of R² at 2-position, 3-position, 4-position,5-position, 6-position, and 7-position represents a 1-carbazolyl grouphaving a substituted or unsubstituted phenyl group, a 2-carbazolyl grouphaving a substituted or unsubstituted phenyl group, a 3-carbazolyl grouphaving a substituted or unsubstituted phenyl group, or a 4-carbazolylgroup having a substituted or unsubstituted phenyl group; the rest of R²represent a hydrogen atom; and FA represents an unsubstituted fusedaromatic cyclic group having 10 to 20 ring carbon atoms.
 12. Thematerial for the organic electroluminescence device according to claim6, wherein: L² represents a single bond or an unsubstituted arylenegroup having 6 to 30 ring carbon atoms; at least one of R² at2-position, 3-position, 4-position, 5-position, 6-position, and7-position represents a substituted or unsubstituted 1-carbazolyl group,a substituted or unsubstituted 2-carbazolyl group, a substituted orunsubstituted 3-carbazolyl group, or a substituted or unsubstituted4-carbazolyl group; R² at 1-position and 8-position represent a hydrogenatom; the rest of R² each independently represent a hydrogen atom, anunsubstituted aryl group having 6 to 30 ring carbon atoms, or anunsubstituted alkyl group having 1 to 30 carbon atoms; and FA representsan unsubstituted fused aromatic cyclic group having 10 to 30 ring carbonatoms.
 13. The material for the organic electroluminescence deviceaccording to claim 6, wherein: L² represents a single bond or anunsubstituted phenylene group; at least one of R² at 2-position,3-position, 4-position, 5-position, 6-position, and 7-positionrepresents a 1-carbazolyl group having a substituted or unsubstitutedphenyl group, a 2-carbazolyl group having a substituted or unsubstitutedphenyl group, a 3-carbazolyl group having a substituted or unsubstitutedphenyl group, or a 4-carbazolyl group having a substituted orunsubstituted phenyl group; the rest of R² represent a hydrogen atom;and FA represents an unsubstituted fused aromatic cyclic group having 10to 20 ring carbon atoms.
 14. The organic electroluminescence deviceaccording to claim 1, wherein FA represents a substituted orunsubstituted naphthyl group, substituted or unsubstituted phenanthrylgroup, substituted or unsubstituted triphenylenyl group, substituted orunsubstituted fluorenyl group, substituted or unsubstituted9,9-dimethylfluorenyl group, substituted or unsubstitutedspirobifluorenyl group, or substituted or unsubstituted fluoranthenylgroup.
 15. The organic electroluminescence device according to claim 1,wherein at least one of R² at 3-position and 6-position represents a1-carbazolyl group having a substituted or unsubstituted phenyl group, a2-carbazolyl group having a substituted or unsubstituted phenyl group, a3-carbazolyl group having a substituted or unsubstituted phenyl group,or a 4-carbazolyl group having a substituted or unsubstituted phenylgroup.
 16. The organic electroluminescence device according to claim 1,wherein L² represents a single bond or an unsubstituted arylene grouphaving 6 to 30 ring carbon atoms.
 17. The organic electroluminescencedevice according to claim 1, wherein: FA represents an unsubstitutednaphthyl group, unsubstituted phenanthryl group, unsubstitutedtriphenylenyl group, unsubstituted fluorenyl group, unsubstituted9,9-dimethylfluorenyl group, unsubstituted spirobifluorenyl group, orunsubstituted fluoranthenyl group, L² represents a single bond or anunsubstituted phenylene group, one of R² at 3-position and 6-positionrepresents a 3-carbazolyl group having a substituted or unsubstitutedphenyl group and the other of R² at 3-position and 6-position representsa hydrogen atom, and R² at 1-position, 2-position, 4-position,5-position, 7-position and 8-position each represents a hydrogen atom.18. The material for the organic electroluminescence device according toclaim 6, wherein FA represents a substituted or unsubstituted naphthylgroup, substituted or unsubstituted phenanthryl group, substituted orunsubstituted triphenylenyl group, substituted or unsubstitutedfluorenyl group, substituted or unsubstituted 9,9-dimethylfluorenylgroup, substituted or unsubstituted spirobifluorenyl group, orsubstituted or unsubstituted fluoranthenyl group.
 19. The material forthe organic electroluminescence device according to claim 6, wherein atleast one of R² at 3-position and 6-position represents a 1-carbazolylgroup having a substituted or unsubstituted phenyl group, a 2-carbazolylgroup having a substituted or unsubstituted phenyl group, a 3-carbazolylgroup having a substituted or unsubstituted phenyl group, or a4-carbazolyl group having a substituted or unsubstituted phenyl group.20. The material for the organic electroluminescence device according toclaim 6, wherein L² represents a single bond or an unsubstituted an_(j)4arylene group having 6 to 30 ring carbon atoms.
 21. The material for theorganic electroluminescence device according to claim 6, wherein FArepresents an unsubstituted naphthyl group, unsubstituted phenanthrylgroup, unsubstituted triphenylenyl group, unsubstituted fluorenyl group,unsubstituted 9,9-dimethylfluorenyl group, unsubstitutedspirobifluorenyl group, or unsubstituted fluoranthenyl group, L²represents a single bond or an unsubstituted phenylene group, one of R²at 3-position and 6-position represents a 3-carbazolyl group having asubstituted or unsubstituted phenyl group and the other of R² at3-position and 6-position represents a hydrogen atom, and R² at1-position, 2-position, 4-position, 5-position, 7-position and8-position each represents a hydrogen atom.
 22. The organicelectroluminescence device according to claim 2, wherein the second hostmaterial is represented by the formula (2) in which FA represents asubstituted or unsubstituted fused aromatic cyclic group having 2 fusedrings.
 23. The material for the organic electroluminescence deviceaccording to claim 6, wherein FA in the formula (2) represents asubstituted or unsubstituted fused aromatic cyclic group having 2 fusedrings.
 24. The organic electroluminescence device according to claim 17,wherein FA represents an unsubstituted naphthyl group, and L² representsa single bond.
 25. The material for the organic electroluminescencedevice according to claim 18, wherein FA represents an unsubstitutednaphthyl group.
 26. The material for the organic electroluminescencedevice according to claim 19, wherein at least one of R² at 3-positionand 6-position represents a 3-carbazolyl group having an unsubstitutedphenyl group.
 27. The material for the organic electroluminescencedevice according to claim 20, wherein L² represents a single bond. 28.The material for the organic electroluminescence device according toclaim 21, wherein FA represents an unsubstituted naphthyl group, L²represents a single bond, and one of R² at 3-position and 6-positionrepresents a 3-carbazolyl group having an unsubstituted phenyl group.